Comparing the pregnancy outcomes of fresh and frozen embryo transfer after early rescue ICSI

Comparing the pregnancy outcomes of fresh and frozen embryo transfer after early rescue ICSI | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Comparing the pregnancy outcomes of fresh and frozen embryo transfer after early rescue ICSI YAN JIANG, JING-CHUAN YUAN, GE SONG, XU-HUI ZHANG, SUI-BING MIAO, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-2596943/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Context: Early-rescue intracytoplasmic sperm injection (R-ICSI) can avoid total fertilization failure in conventional in vitro fertilization (IVF). However, the R-ICSI embryos had lower implantation rate than the direct ICSI in the fresh embryo transfer. Aims: To investigate the effect of frozen embryo transfer (FET)after R-ICSI. Methods : This was a retrospective study of the first cycle primary infertility patients with the age ≤ 35 undergoing R-ICSI and ICSI treatment. The clinical pregnancy rate, implantation rate, ectopic pregnancy, abortion rate and live birth rate were analyzed between the R-ICSI and ICSI groups in their first embryo transfer (fresh and FET cycles). Key Results : The average age of patients in fresh and frozen ET of two groups was (29.1±3.1 vs. 29.0±3.2, and 28.9±3.0 vs. 29.1±3.3), respectively ( P> 0.05). The R-ICSI embryos clinical pregnancy rate, implantation rate and live birth rate were lower than the ICSI embryos in fresh embryo transfer. Whereas there were no significant difference between R-ICSI and ICSI embryos in the FET cycle. Conclusions: R-ICSI embryos with frozen embryo transfer would be an optimal strategy rather than fresh embryo transfers. Implications: early R-ICSI combined with frozen embryo transfer could achieve satisfying clinical outcomes compared with fresh embryo transfers. Total fertilization failure early-rescue ICSI frozen embryo transfer clinical outcomes Figures Figure 1 Introduction Intracytoplasmic sperm injection (ICSI) was introduced in the early 1990s to treat severe male infertility. There is insufficient evidence to suggest ICSI use in couples without male factor infertility (Paffoni et al. 2021 ). To avoid total fertilization failure or low fertilization in conventional in vitro fertilization (IVF), short co-incubation of gametes combined with early-rescue intracytoplasmic sperm injection (R-ICSI) is an optimal strategy (Zeng et al. 2022 ). Some studies indicated that short insemination had no detrimental effects on clinical outcomes in human IVF and early R-ICSI could attain acceptable pregnancy outcomes(He et al. 2018 ). However, the R-ICSI embryos had lower implantation rate than the direct ICSI group in the fresh embryo transfer, for the sperms were microinjected into oocytes 4–6 h later compared with those in the ICSI group (Zeng et al. 2022 ). A meta-analysis about couples with TFF following conventional IVF cycles (the co-culture of oocytes and cumulus cells for 18–20 h) showed that late R-ICSI coupled with frozen embryo transfer had much higher clinical pregnancy rate compared with fresh embryo transfers(Paffoni et al. 2021 ). If the early R-ICSI embryo would be beneficial with frozen embryo transfer is still unknown. The purpose of the present study was to retrospectively investigate the clinical outcomes of embryos derived from R-ICSI and direct ICSI cycles be transferred in fresh and in a frozen-thawed cycles. Patients And Methods Patients This was a retrospective cohort study carried out at the Center for Reproductive Medicine and Infertility, the Fourth Hospital of Shijiazhuang, from January 2016 to November 2021. The patients included in the analysis were primary infertility, age ≤ 35 years, retrieved oocytes ≥ 5 in their first short-term IVF + Re-ICSI cycle or directly ICSI treatment because of severe oligospermia, undergoing their first embryo transfer (ET), including fresh ET or frozen embryo transfer (FET). The inclusion criteria were the following: Female undergoing their first Re-ICSI/ICSI cycle with D3 two high quality cleavage ET in fresh cycle, or single vitrified-warmed blastocyst transfer (SVBT) with D5 high quality blastocyst in their first FET cycle (all embryo frozen ) (Fig. 1 ). The exclusion criteria included use of donor eggs/sperm, patients with oocyte maturation disorder, chromosomal abnormalities, hyperprolactinemia, thyroid dysfunction, women with congenital or secondary uterine abnormalities such as unicornuate uterus, septate uterus or uterine didelphys, adenomyosis, uterine submucosal fifibroids, intrauterine adhesions, endometriosis, or other endometrial disease, or endometrial thickness < 7 mm on the day of embryo transfer. A total of 293 early R-ICSI cycles and 326 ICSI cycles were enrolled in this study, which were divided in fresh ET 313 cycles (R-ICSI 151 cycles, ICSI 162 cycles) and FET 306 cycles (R-ICSI 142 cycles, ICSI 164 cycles). All the procedures in this study were not experimental and have already been performed in many IVF centers under different criteria. This study did not get consent from the patient, because data were collected and anonymized in accordance with the ethical standards of the ethics committee as per the principles originating from the Declaration of Helsinki. This study was approved by the Research Ethics Committee of the Fourth Hospital of Shijiazhuang (approval no. 20220049). Stimulation, Oocyte Retrieval, Fertilization, Embryo Culture And Scoring Ovarian stimulation and oocyte retrieval has been previously described by Yan Jiang, et al. (Jiang et al. 2013 ). Sperm used for routine IVF insemination procedure using a standard method. Insemination were performed after 38 ~ 40 h of trigger. Each oocyte is incubated with approximately 20,000 sperm cells. Short co-incubation was adopted, and the cumulus granule cells were peeled of 4–6 h after fertilization. In patients with a missing second polar body in any of the retrieved oocytes or with a low fertilization rate (< 30%), the MII oocytes would be rescued to undergo the same ICSI method (early R-ICSI cycle) at about 6 h after fertilization(Jiang et al. 2013 ). Oocytes used for ICSI directly were treated with bovine hyaluronidase (Sigma-Aldrich, St Louis, MO, USA) for dispersing the cumulus cells after 39 ~ 40 h of trigger. “High quality embryos” should have 7–9 cells on day 3, contain less than 20% fragments, but might be a little uneven in appearance. On day 3 two high quality embryos were selected for embryo transfer, basis on endometrial factors, ovarian hyperstimulation syndrome (OHSS) occurred or personal reasons. Other embryos transferred into G-2 culture medium in group culture (Vitrolife, Sweden). In the morning of D5 or D6, blastocysts were scored by two experienced embryologist using the system of Gardner and Schoolcraft (Gardner et al. 1999). “High quality blastocysts”were score ≥ 3BB blastocysts Blastocyst Vitrification And Warming Procedures The procedure was always performed using one blastocyst for each straw. An artificial shrinkage (AS), using a laser pulse was performed before vitrification. The blastocyst was then moved at room temperature (22–25°C) to Kitazato (Japan) equilibration solution (ES). After 6–8 min, the blastocyst was quickly washed in vitrification solution (VS) for 45–60s and transferred onto the straw (Kitazato Japan) using a micropipette and immersed vertically into liquid nitrogen(Jiang et al. 2022 ). Hormone therapy cycles were used as the endometrial preparation for the FET. An Kitazato (Japan) Thaw Kit was used for warming. The carrier containing the embryo was removed from the straw and placed quickly into the dish containing the thawing medium (thawing solution) preheated at 37°C. The blastocysts immediately fell from the device and could be easily identified in the medium. After 1 min, blastocysts were transferred to the DS medium (dilution solution) for 3 min at room temperature 22–25°C. In the last two step, blastocysts were placed for 5 min, in the WS1 medium and WS2 (washing solution). The embryo was then returned to G-2 medium for culture until transfer. At this stage, an assessment was performed on an inverted microscope to establish if the embryo survived based on morphological integrity of the ICM and trophectoderm. After 1 or 2 h of culture the embryo was reassessed again and often the re-expansion of the blastocoel was reported; this indicated that the embryo physiologically survived the warming procedure. Embryo transfer was normally performed within 2 or 3 h (Jiang et al. 2022 ). Clinical Outcome Clinical outcome B ultrasound was used to observe the gestational sac and fetal heart at 35 days after implantation was diagnosed as clinical pregnancy. Implantation rate was defined as the ratio of the number of gestational sacs and fetal heart observed under B ultrasound and the number of transferred embryos(Jiang et al. 2022 ). The clinical pregnancy rate, implantation rate, ectopic pregnancy, abortion rate and live birth rate were analyzed. Data Analysis Statistical analyses were performed using SPSS 19.0 statistical software (SPSS Inc.). The results are presented as the mean ± standard deviation (SD). The mean values of two groups were compared using the independent samples t-test. Percentages were compared using the χ2 test and P < 0.05 was considered statistically significant. Results 1. The pregnancy outcomes of fresh ET in R-ICSI and ICSI groups. In 313 fresh ET cycles, R-ICSI 151 cycles, ICSI 162 cycles. The average age and body mass index (BMI) of patients in two groups was (29.0 ± 3.2 vs. 29.1 ± 3.1, and 23.9 ± 4.2 vs. 23.7 ± 4.2), respectively ( P > 0.05). The rates of clinical pregnancy, implantation and live birth in R-ICSI group were lower than ICSI group in fresh ET cycles ( P < 0.05). No signifcant diferences were observed in the ectopic pregnancy rate, abortion rate and sex ratio in the two groups (Table 1 ). 2. The pregnancy outcomes of FET in R-ICSI and ICSI groups. In 306 FET cycles, R-ICSI 142 cycles, ICSI 164 cycles. The D5 high quality blastocyst survive rate was 100% in two groups of SVBT cycles. The average age and body mass index (BMI) of patients in two groups was (29.1 ± 3.3 vs. 28.9 ± 3.0, and 23.4 ± 3.9 vs. 23.2 ± 3.8), respectively ( P > 0.05). Rates of clinical pregnancy, implantation, ectopic pregnancy, abortion, sex ratio, and live birth were not significantly different in the two groups in SVBT cycle (Table 2 ). Table 1 ICSI and R-ICSI embryo in fresh ET cycles R-ICSI ICSI χ 2 / t P ET 2 cleavage embryo cycle (n) 151 162 Patient age (years) 29.0 ± 3.2 29.1 ± 3.1 1.410 0.160 infertility duration (years) 3.6 ± 2.7 3.5 ± 2.5 1.551 0.122 BMI (kg/m2) 23.9 ± 4.2 23.7 ± 4.2 0.148 0.882 Clinical pregnancy rate (%) 52.3 (79/151) 64.2 (104/162) 4.542 0.033* Implantation rate (%) 34.4 (104/302) 42.3 (137/324) 4.065 0.044* Ectopic pregnancy rate(%) 0 (0/90) 1.9 (2/104) 1.749 0.186 Abortion rate(%) 10.0 (8/79) 11.5 (12/104) 0.092 0.762 Sex ratio (male/female) 1.23 (49/40) 1.09 (61/56) 0.173 0.677 Live birth rate (%) 58.9 (89/151) 69.4 (117/162) 6.128 0.013* (* P < 0.05) Table 2 ICSI and R-ICSI embryo in SVBT cycles R-ICSI ICSI χ 2 / t P FET blastocyst cycle 142 164 Patient age (years) 29.1 ± 3.3 28.9 ± 3.0 1.490 0.138 infertility duration (years) 3.5 ± 2.7 3.4 ± 2.4 1.141 0.255 BMI(kg/m2) 23.4 ± 3.9 23.2 ± 3.8 1.774 0.078 Clinical pregnancy rate (%) 68.3 (97/142) 68.3 (112/164) 0.000 1.000 Implantation rate (%) 70.4 (100/142) 70.1 (115/164) 0.003 0.954 ectopic pregnancy(%) 1.0 (1/97) 0 (0/112) 1.160 0.281 Abortion rate(%) 17.5 (17/97) 17.9 (20/112) 0.004 0.950 Sex ratio (male/female) 1.45 (48/33) 1.19 (51/43) 0.443 0.505 Live birth rate(%) 57.0 (81/142) 57.3 (94/164) 0.002 0.961 Discussion Previous pregnancy history, duration of infertility, forward-moving sperm counts, and abnormal sperm rate have significance to predict fertilization failure, so whether a patient should conduct short-time insemination should based on the above indexes (Guo et al. 2012 ). During the procedures of short co-incubation, patients presented a less than 30% fertilization rate and underwent early R-ICSI treatment. Early R-ICSI was carried out to reduce the occurrence of total fertilization failure (TFF) and near-total fertilization failure (NFF) (Paffoni et al. 2021 ). The incidence of NFF was 6.49% (864/13,317), whereas that of TFF was 4.21% (561/13,317)(Zeng et al. 2022 ). When is the right time to perform R-ICSI that can achieve a better outcome (Zeng et al. 2022 )? For the second polar body at more or less 6 h, performing R-ICSI after 6 h of coincubation can salvage cases with fertilization failure in IVF. The higher fertilization rate of R-ICSI indicates that all oocytes without signs of fertilization after 6 h of coincubation should undergo R-ICSI (Shiraiwa et al. 2021 ). However, the effectiveness of early R-ICSI remains debatable. In the study of the sibling eggs were divided into conventional insemination and short insemination combined with R-ICSI if required. There were 11 cycles in which R-ICSI was performed due to TFF occurring in the eggs with the short insemination. While in 6 of these cycles, fertilization occurred in the patient's eggs in the 20 h insemination group (Liu et al. 2016 ). Although the early cumulus cell removal alone (4 h) had similar pregnancy outcomes compared with conventional cumulus cell removal after 20 hours of insemination (Kong et al. 2021 ). However, the pregnancy outcomes of R-ICSI embryos in fresh cycles remains controversial. Zeng J et al. showed that the R-ICSI embryos had lower rates of implantation than the ICSI embryos in fresh embryo transfer. Whereas Jiang L et al. showed that rates of implantation, clinical pregnancy, and live birth were similar in the early R-ICSI and ICSI groups(Jiang et al. 2021 ). (The reason maybe they did not emphasize all transfer embryo origin from R-ICSI, and the cases is small, only 7 cycles were included.) And the the pregnancy outcomes of R-ICSI and ICSI embryos in FET cycles is less reported. In this study, we selected primary infertility patients with age ≤ 35 years and ≥ 5 oocytes in their first Re-ICSI/ICSI cycle to minimize the influence of age and oocytes factor. In the early R-ICSI cycles, especially part of oocytes R-ICSI cycles, the embryos come from short-term insemination embryos and R-ICSI embryos together(Zeng et al. 2022 ). In this study, the embryos transferred all from R-ICSI fertilizaion. We choose D3 two high quality embryos in the first fresh cleavage-stage ET cycles, or SVBT (all embryo frozen) with D5 high quality blastocyst in their first FET cycle to reduce the effects of embryo and ET frequency. Another reason for choosing D5 blastocysts with high quality is that they have a 100% survival rate in the SVBT cycle. Our study showed that the R-ICSI embryos clinical pregnancy rate, implantation rate and live birth rate were lower than the ICSI embryos in fresh embryo transfer. Whereas there were no significant difference between R-ICSI and ICSI embryos in the FET cycle. There were two differences in R-ICSI/ICSI groups, one is dispersing the cumulus cells method, another is fertilization time. In the R-ICSI group, the sperms were micro-injected into oocytes 4–6 h later compared with those in the ICSI group. The differences of pregnancy outcomes of R-ICSI/ICSI probably because of the oocyte aging and subsequent embryonic development(Zeng et al. 2022 ). Whereas from the results of our study, we know that R-ICSI/ICSI embryo had similar pregnancy outcomes in FET cycle. This certificated that R-ICSI/ICSI embryo had similar competent of development. The lower pregnancy outcomes of R-ICSI embryo in fresh ET cycle probably because the fertilization time 4–6 h later than ICSI, leading to asynchronized endometrium. We know that late R-ICSI (18–20 h) lead to poor clinical pregnancy outcome resulting from oocyte aging (Lombardi et al. 2003) and asynchronization between endometrial growth and embryo development (Sermondade et al. 2021). However, frozen embryo transfer seemed to improve with pregnancy rates and implantation rate in late R-ICSI patients(Paffoni et al. 2021 ). The strategy of cryopreservation could overcome the loss of synchronization between endometrial growth and late R-ICSI embryo development (Paffoni et al. 2021 ). In early R-ICSI cycles, unfertilized oocytes by ICSI only 6h later instead of nearly 1-day-old in late R-ICSI. So the influences of oocyte aging and asynchronization between endometrial growth and embryo development was minor compared with late R-ICSI. But the results of our study about embryos from early R-ICSI were similar with late R-ICSI. In consideration of fresh cleavage-stage ET cycles could make negative effects on the clinical outcomes after R-ICSI. In early R-ICSI cycles, if a patient had both IVF and R-ICSI embryos, IVF embryos should be preferred in fresh ET with the same embryo score, while R-ICSI embryos preferred to cryopreservation. The limitation of the study was not distinguish the R-ICSI embryo according the micro-injecting time. In conclusion, our results clearly show that early R-ICSI combined with frozen embryo transfer could achieve satisfying clinical outcomes compared with fresh embryo transfers. Therefore, the strategy of cryopreservation could overcome the technical and biological issues of the loss of synchronization between endometrial growth and embryo development associated with R-ICSI. Declarations Ethics approval and consent to participate The Fourth Hospital of Shijiazhuang Ethics Committee approved this study (approval no. 20220049). Informed consent was obtained from all subjects. The procedures used in this study adhered to the tenets of the Declaration of Helsinki. All experiments were performed in accordance with relevant guidelines and regulations. Consent for publication Not applicable Availability of data and materials The datasets used during the present study are available from the corresponding author upon reasonable request. Data will be made available to the editors of the journal for review or query upon request. Competing interests All authors declare no conflict of interest. Funding Hebei Province Medical Science Research Key Project（20231650） Authors' contributions YAN JIANG, XIAO-HUA WU and JING-CHUAN YUAN wrote the main manuscript text. GE SONG, XU-HUI ZHANG and SUI-BING MIAO prepared table 1-2. and figures 1. All authors reviewed the manuscript. All authors read and approved the manuscript and agree to be accountable for all aspects of the research in ensuring that the accuracy or integrity of any part of the work are appropriately investigated and resolved. Acknowledgements Not applicable Authors' information (optional) Not applicable References Gardner DK, Schoolcraft WB. (1999) Culture and transfer of human blastocysts. Curr Opin Obstet Gynecol 11(3): 307–311.doi: 10.1097/00001703-199906000-00013 . PMID: 10369209. Guo H, Yang J, Zhang C, Li H, Yin B, Gu B, Xie J, He Q. (2012) Analysis of clinical data of patients with different outcomes after short-time insemination. Andrologia. 44 Suppl 1:667 – 71. doi: 10.1111/j.1439-0272.2011.01247.x . Epub 2011 Dec 2. PMID: 22136561. He Y, Liu H, Zheng H, Li L, Fu X, Liu J. Effect of early cumulus cells removal and early rescue ICSI on pregnancy outcomes in high-risk patients of fertilization failure. Gynecol Endocrinol. 2018;34(8):689–93. Epub 2018 Feb 15. PMID: 29448847. Jiang L, Qian Y, Chen X, Ji X, Ou S, Li R, Yang D, Li Y. Effect of early rescue ICSI and split IVF-ICSI in preventing low fertilization rate during the first ART cycle: A real-world retrospective cohort study. Reprod Med Biol. 2021;27(1):e12420. 10.1002/rmb2.12420 . PMID: 34934401; PMCID: PMC8656193. Jiang Y, Cao Q, Zhao X, Li L, Li S, Gao F. Percutaneous epididymal sperm aspiration and short time insemination in the treatment of men with obstructive azoospermia. J Assist Reprod Genet. 2013;30(9):1175–9. 10.1007/s10815-013-0075-1 . Epub 2013 Aug 29. PMID: 23989999; PMCID: PMC3800539. Jiang Y, Song G, Zhang XH, Miao SB, Wu XH. Frozen blastocysts: Assessing the importance of day 5/day 6 blastocysts or blastocyst quality. Exp Ther Med. 2022;23(5):333. 10.3892/etm.2022.11262 . Epub 2022 Mar 16. PMID: 35401807; PMCID: PMC8987946. Kong P, Yin M, Tang C, Zhu X, Bukulmez O, Chen M, Teng X. Effects of early cumulus cell removal on treatment outcomes in patients undergoing in vitro fertilization: A retrospective cohort study. Front Endocrinol (Lausanne). 2021;12:669507. 10.3389/fendo.2021.669507 . PMID: 34025582; PMCID: PMC8138552. Liu J, Zhang X, Yang Y, Zhao J, Hao D, Zhang J, Liu Y, Wu W, Wang X. Long-time vs. short-time insemination of sibling eggs. Exp Ther Med. 2016;12(6):3756–60. 10.3892/etm.2016.3827 . Epub 2016 Oct 20. PMID: 28105107; PMCID: PMC5228384. Lombardi E. Live birth and normal 1-year follow-up of a baby born after transfer of cryopreserved embryos from rescue intracytoplasmic sperm injection of 1-day-old oocytes. Fertil Steril. 2003;80:646–8. https://doi.org/10.1016/S0015-0282(03)00996-8 . Paffoni A, Reschini M, Pisaturo V, Guarneri C, Palini S, Viganò P. Should rescue ICSI be re-evaluated considering the deferred transfer of cryopreserved embryos in in-vitro fertilization cycles? A systematic review and meta-analysis. Reprod Biol Endocrinol. 2021;4(1):121. 10.1186/s12958-021-00784-3 . PMID: 34348713; PMCID: PMC8336078. Sermondade N, Hugues J, Cedrin-Durnerin I, Poncelet C, Benzacken B, Lévy R, Sifer C. Should all embryos from day 1 rescue intracytoplasmic sperm injection be transferred during frozen–thawed cycles? Fertil Steril. 2010;94:1157–8. https://doi.org/10.1016/j.fertnstert.2009.12.001 . Shiraiwa Y, Enatsu N, Yamagami K, Furuhashi K, Iwasaki T, Otsuki J, Shiotani M. Clinical Outcomes of Rescue Intracytoplasmic Sperm Injection at Different Timings Following In Vitro Fertilization. J Reprod Infertil. 2021;22(4):251–7. 10.18502/jri.v22i4.7650 . PMID: 34987986; PMCID: PMC8669413. Zeng J, Yao Z, Zhang Y, Tian F, Liao T, Wu L, Li Y. Fertilization and neonatal outcomes after early rescue intracytoplasmic sperm injection: a retrospective analysis of 16,769 patients. Arch Gynecol Obstet. 2022;306(1):249–58. 10.1007/s00404-022-06445-z . Epub 2022 Apr 5. PMID: 35380279; PMCID: PMC9300487. Additional Declarations No competing interests reported. Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-2596943","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":180759339,"identity":"487f5509-6968-4cf0-8c83-5e2a48fe569f","order_by":0,"name":"YAN JIANG","email":"","orcid":"","institution":"The Fourth Hospital of Shijiazhuang","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"YAN","middleName":"","lastName":"JIANG","suffix":""},{"id":180759340,"identity":"97045032-0755-4fed-a410-0af1f7b35539","order_by":1,"name":"JING-CHUAN YUAN","email":"","orcid":"","institution":"The Fourth Hospital of Shijiazhuang","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"JING-CHUAN","middleName":"","lastName":"YUAN","suffix":""},{"id":180759341,"identity":"2c2b0794-ec3e-42a8-9706-23c2d9a3d1a4","order_by":2,"name":"GE SONG","email":"","orcid":"","institution":"The Fourth Hospital of Shijiazhuang","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"GE","middleName":"","lastName":"SONG","suffix":""},{"id":180759342,"identity":"c296dc95-264d-40e2-b529-b8ed6e2de86b","order_by":3,"name":"XU-HUI ZHANG","email":"","orcid":"","institution":"The Fourth Hospital of Shijiazhuang","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"XU-HUI","middleName":"","lastName":"ZHANG","suffix":""},{"id":180759343,"identity":"ab72b0f6-f0e6-4245-a993-8c292d52a369","order_by":4,"name":"SUI-BING MIAO","email":"","orcid":"","institution":"The Fourth Hospital of Shijiazhuang","correspondingAuthor":false,"submittingAuthor":false,"prefix":"","firstName":"SUI-BING","middleName":"","lastName":"MIAO","suffix":""},{"id":180759344,"identity":"a29f4e60-30fd-4f09-b70b-c5b313c94290","order_by":5,"name":"XIAO-HUA WU","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAA60lEQVRIiWNgGAWjYDACZjBikONnbz744AMDQwLRWowle44lG84gSgtEF0Pihhs+asI8xGgxOM788HFhmx1QCw8bs22bXR4/ewPjh485uLVINrMZG89sSzaeebv32OPctuRiyZ4DzJIzt+HWws/MYCbN28Ys23fnXLpxbhsz0LoENmZePFrYmNm/AbXUMzbcyDGTtmyrJ6yFn5kHZMthxQkgLYxthwlrkWzmKTbmOXccEsg9544nzuw52IzXLwbnj298zFNWDYnKH2XVif1AxoePeLSgAkY2MNlArHoQ+EOK4lEwCkbBKBgpAAA5WlJbFBjTAwAAAABJRU5ErkJggg==","orcid":"","institution":"The Fourth Hospital of Shijiazhuang","correspondingAuthor":true,"submittingAuthor":false,"prefix":"","firstName":"XIAO-HUA","middleName":"","lastName":"WU","suffix":""}],"badges":[],"createdAt":"2023-02-17 02:59:15","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-2596943/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-2596943/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":34041508,"identity":"f7c1daab-35a6-4575-8402-691b274cedc4","added_by":"auto","created_at":"2023-03-10 00:00:30","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":92977,"visible":true,"origin":"","legend":"\u003cp\u003eFresh and frozen embryo transfer of ICSI and R-ICSI embryo.\u003c/p\u003e","description":"","filename":"floatimage1.png","url":"https://assets-eu.researchsquare.com/files/rs-2596943/v1/927940a9c8064bd106b1b284.png"},{"id":34654873,"identity":"4d607726-cdfb-4c27-954a-ede4e3d8841a","added_by":"auto","created_at":"2023-03-22 14:45:08","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":346003,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-2596943/v1/495fba06-bcef-4501-99f9-324773992b6c.pdf"}],"financialInterests":"No competing interests reported.","formattedTitle":"Comparing the pregnancy outcomes of fresh and frozen embryo transfer after early rescue ICSI","fulltext":[{"header":"Introduction","content":"\u003cp\u003eIntracytoplasmic sperm injection (ICSI) was introduced in the early 1990s to treat severe male infertility. There is insufficient evidence to suggest ICSI use in couples without male factor infertility (Paffoni et al. \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). To avoid total fertilization failure or low fertilization in conventional in vitro fertilization (IVF), short co-incubation of gametes combined with early-rescue intracytoplasmic sperm injection (R-ICSI) is an optimal strategy (Zeng et al. \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2022\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eSome studies indicated that short insemination had no detrimental effects on clinical outcomes in human IVF and early R-ICSI could attain acceptable pregnancy outcomes(He et al. \u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e2018\u003c/span\u003e). However, the R-ICSI embryos had lower implantation rate than the direct ICSI group in the fresh embryo transfer, for the sperms were microinjected into oocytes 4\u0026ndash;6 h later compared with those in the ICSI group (Zeng et al. \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2022\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eA meta-analysis about couples with TFF following conventional IVF cycles (the co-culture of oocytes and cumulus cells for 18\u0026ndash;20 h) showed that late R-ICSI coupled with frozen embryo transfer had much higher clinical pregnancy rate compared with fresh embryo transfers(Paffoni et al. \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). If the early R-ICSI embryo would be beneficial with frozen embryo transfer is still unknown.\u003c/p\u003e \u003cp\u003eThe purpose of the present study was to retrospectively investigate the clinical outcomes of embryos derived from R-ICSI and direct ICSI cycles be transferred in fresh and in a frozen-thawed cycles.\u003c/p\u003e \u003cdiv id=\"Sec2\" class=\"Section2\"\u003e \u003c/div\u003e"},{"header":"Patients And Methods","content":"\n\u003ch3\u003ePatients\u003c/h3\u003e\n\u003cp\u003eThis was a retrospective cohort study carried out at the Center for Reproductive Medicine and Infertility, the Fourth Hospital of Shijiazhuang, from January 2016 to November 2021. The patients included in the analysis were primary infertility, age\u0026thinsp;\u0026le;\u0026thinsp;35 years, retrieved oocytes\u0026thinsp;\u0026ge;\u0026thinsp;5 in their first short-term IVF\u0026thinsp;+\u0026thinsp;Re-ICSI cycle or directly ICSI treatment because of severe oligospermia, undergoing their first embryo transfer (ET), including fresh ET or frozen embryo transfer (FET).\u003c/p\u003e \u003cp\u003eThe inclusion criteria were the following: Female undergoing their first Re-ICSI/ICSI cycle with D3 two high quality cleavage ET in fresh cycle, or single vitrified-warmed blastocyst transfer (SVBT) with D5 high quality blastocyst in their first FET cycle (all embryo frozen ) (Fig.\u0026nbsp;\u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eThe exclusion criteria included use of donor eggs/sperm, patients with oocyte maturation disorder, chromosomal abnormalities, hyperprolactinemia, thyroid dysfunction, women with congenital or secondary uterine abnormalities such as unicornuate uterus, septate uterus or uterine didelphys, adenomyosis, uterine submucosal fifibroids, intrauterine adhesions, endometriosis, or other endometrial disease, or endometrial thickness\u0026thinsp;\u0026lt;\u0026thinsp;7 mm on the day of embryo transfer.\u003c/p\u003e \u003cp\u003eA total of 293 early R-ICSI cycles and 326 ICSI cycles were enrolled in this study, which were divided in fresh ET 313 cycles (R-ICSI 151 cycles, ICSI 162 cycles) and FET 306 cycles (R-ICSI 142 cycles, ICSI 164 cycles).\u003c/p\u003e \u003cp\u003eAll the procedures in this study were not experimental and have already been performed in many IVF centers under different criteria. This study did not get consent from the patient, because data were collected and anonymized in accordance with the ethical standards of the ethics committee as per the principles originating from the Declaration of Helsinki. This study was approved by the Research Ethics Committee of the Fourth Hospital of Shijiazhuang (approval no. 20220049).\u003c/p\u003e\n\u003ch3\u003eStimulation, Oocyte Retrieval, Fertilization, Embryo Culture And Scoring\u003c/h3\u003e\n\u003cp\u003eOvarian stimulation and oocyte retrieval has been previously described by Yan Jiang, et al. (Jiang et al. \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2013\u003c/span\u003e). Sperm used for routine IVF insemination procedure using a standard method. Insemination were performed after 38\u0026thinsp;~\u0026thinsp;40 h of trigger. Each oocyte is incubated with approximately 20,000 sperm cells. Short co-incubation was adopted, and the cumulus granule cells were peeled of 4\u0026ndash;6 h after fertilization. In patients with a missing second polar body in any of the retrieved oocytes or with a low fertilization rate (\u0026lt;\u0026thinsp;30%), the MII oocytes would be rescued to undergo the same ICSI method (early R-ICSI cycle) at about 6 h after fertilization(Jiang et al. \u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e2013\u003c/span\u003e). Oocytes used for ICSI directly were treated with bovine hyaluronidase (Sigma-Aldrich, St Louis, MO, USA) for dispersing the cumulus cells after 39\u0026thinsp;~\u0026thinsp;40 h of trigger.\u003c/p\u003e \u003cp\u003e\u0026ldquo;High quality embryos\u0026rdquo; should have 7\u0026ndash;9 cells on day 3, contain less than 20% fragments, but might be a little uneven in appearance. On day 3 two high quality embryos were selected for embryo transfer, basis on endometrial factors, ovarian hyperstimulation syndrome (OHSS) occurred or personal reasons. Other embryos transferred into G-2 culture medium in group culture (Vitrolife, Sweden). In the morning of D5 or D6, blastocysts were scored by two experienced embryologist using the system of Gardner and Schoolcraft (Gardner et al. 1999). \u0026ldquo;High quality blastocysts\u0026rdquo;were score\u0026thinsp;\u0026ge;\u0026thinsp;3BB blastocysts\u003c/p\u003e\n\u003ch3\u003eBlastocyst Vitrification And Warming Procedures\u003c/h3\u003e\n\u003cp\u003eThe procedure was always performed using one blastocyst for each straw. An artificial shrinkage (AS), using a laser pulse was performed before vitrification. The blastocyst was then moved at room temperature (22\u0026ndash;25\u0026deg;C) to Kitazato (Japan) equilibration solution (ES). After 6\u0026ndash;8 min, the blastocyst was quickly washed in vitrification solution (VS) for 45\u0026ndash;60s and transferred onto the straw (Kitazato Japan) using a micropipette and immersed vertically into liquid nitrogen(Jiang et al. \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2022\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eHormone therapy cycles were used as the endometrial preparation for the FET. An Kitazato (Japan) Thaw Kit was used for warming. The carrier containing the embryo was removed from the straw and placed quickly into the dish containing the thawing medium (thawing solution) preheated at 37\u0026deg;C. The blastocysts immediately fell from the device and could be easily identified in the medium. After 1 min, blastocysts were transferred to the DS medium (dilution solution) for 3 min at room temperature 22\u0026ndash;25\u0026deg;C. In the last two step, blastocysts were placed for 5 min, in the WS1 medium and WS2 (washing solution). The embryo was then returned to G-2 medium for culture until transfer. At this stage, an assessment was performed on an inverted microscope to establish if the embryo survived based on morphological integrity of the ICM and trophectoderm. After 1 or 2 h of culture the embryo was reassessed again and often the re-expansion of the blastocoel was reported; this indicated that the embryo physiologically survived the warming procedure. Embryo transfer was normally performed within 2 or 3 h (Jiang et al. \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2022\u003c/span\u003e).\u003c/p\u003e\n\u003ch3\u003eClinical Outcome\u003c/h3\u003e\n\u003cdiv class=\"Heading\"\u003eClinical outcome\u003c/div\u003e \u003cp\u003eB ultrasound was used to observe the gestational sac and fetal heart at 35 days after implantation was diagnosed as clinical pregnancy. Implantation rate was defined as the ratio of the number of gestational sacs and fetal heart observed under B ultrasound and the number of transferred embryos(Jiang et al. \u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). The clinical pregnancy rate, implantation rate, ectopic pregnancy, abortion rate and live birth rate were analyzed.\u003c/p\u003e \u003cdiv id=\"Sec7\" class=\"Section2\"\u003e \u003ch2\u003eData Analysis\u003c/h2\u003e \u003cp\u003eStatistical analyses were performed using SPSS 19.0 statistical software (SPSS Inc.). The results are presented as the mean\u0026thinsp;\u0026plusmn;\u0026thinsp;standard deviation (SD). The mean values of two groups were compared using the independent samples t-test. Percentages were compared using the χ2 test and \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05 was considered statistically significant.\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003e1. The pregnancy outcomes of fresh ET in R-ICSI and ICSI groups.\u003c/p\u003e\n\u003cp\u003eIn 313 fresh ET cycles, R-ICSI 151 cycles, ICSI 162 cycles. The average age and body mass index (BMI) of patients in two groups was (29.0\u0026thinsp;\u0026plusmn;\u0026thinsp;3.2 vs. 29.1\u0026thinsp;\u0026plusmn;\u0026thinsp;3.1, and 23.9\u0026thinsp;\u0026plusmn;\u0026thinsp;4.2 vs. 23.7\u0026thinsp;\u0026plusmn;\u0026thinsp;4.2), respectively (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05). The rates of clinical pregnancy, implantation and live birth in R-ICSI group were lower than ICSI group in fresh ET cycles (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05). No signifcant diferences were observed in the ectopic pregnancy rate, abortion rate and sex ratio in the two groups (Table \u003cspan class=\"InternalRef\"\u003e1\u003c/span\u003e).\u003c/p\u003e\n\u003cp\u003e2. The pregnancy outcomes of FET in R-ICSI and ICSI groups.\u003c/p\u003e\n\u003cp\u003eIn 306 FET cycles, R-ICSI 142 cycles, ICSI 164 cycles. The D5 high quality blastocyst survive rate was 100% in two groups of SVBT cycles. The average age and body mass index (BMI) of patients in two groups was (29.1\u0026thinsp;\u0026plusmn;\u0026thinsp;3.3 vs. 28.9\u0026thinsp;\u0026plusmn;\u0026thinsp;3.0, and 23.4\u0026thinsp;\u0026plusmn;\u0026thinsp;3.9 vs. 23.2\u0026thinsp;\u0026plusmn;\u0026thinsp;3.8), respectively (\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026gt;\u0026thinsp;0.05). Rates of clinical pregnancy, implantation, ectopic pregnancy, abortion, sex ratio, and live birth were not significantly different in the two groups in SVBT cycle (Table \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e).\u003c/p\u003e\n\u003cdiv class=\"gridtable\"\u003e\u0026nbsp;\u003ctable border=\"1\" id=\"Tab1\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eICSI and R-ICSI embryo in fresh ET cycles\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003ccolgroup cols=\"5\"\u003e\u003c/colgroup\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eR-ICSI\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eICSI\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e\u0026chi;\u003csup\u003e2\u003c/sup\u003e\u003cem\u003e/ t\u003c/em\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eP\u003c/em\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eET 2 cleavage embryo cycle (n)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e151\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e162\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePatient age (years)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e29.0\u0026thinsp;\u0026plusmn;\u0026thinsp;3.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e29.1\u0026thinsp;\u0026plusmn;\u0026thinsp;3.1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.410\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.160\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003einfertility duration (years)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3.6\u0026thinsp;\u0026plusmn;\u0026thinsp;2.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3.5\u0026thinsp;\u0026plusmn;\u0026thinsp;2.5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.551\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.122\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eBMI (kg/m2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e23.9\u0026thinsp;\u0026plusmn;\u0026thinsp;4.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e23.7\u0026thinsp;\u0026plusmn;\u0026thinsp;4.2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.148\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.882\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eClinical pregnancy rate (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e52.3\u003c/p\u003e\n \u003cp\u003e(79/151)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e64.2\u003c/p\u003e\n \u003cp\u003e(104/162)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e4.542\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.033*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eImplantation rate (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e34.4\u003c/p\u003e\n \u003cp\u003e(104/302)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e42.3\u003c/p\u003e\n \u003cp\u003e(137/324)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e4.065\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.044*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eEctopic pregnancy rate(%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003cp\u003e(0/90)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.9\u003c/p\u003e\n \u003cp\u003e(2/104)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.749\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.186\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAbortion rate(%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10.0\u003c/p\u003e\n \u003cp\u003e(8/79)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e11.5\u003c/p\u003e\n \u003cp\u003e(12/104)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.092\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.762\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSex ratio (male/female)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.23\u003c/p\u003e\n \u003cp\u003e(49/40)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.09\u003c/p\u003e\n \u003cp\u003e(61/56)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.173\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.677\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eLive birth rate (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e58.9\u003c/p\u003e\n \u003cp\u003e(89/151)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e69.4\u003c/p\u003e\n \u003cp\u003e(117/162)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e6.128\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.013*\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003ctfoot\u003e\n \u003ctr\u003e\n \u003ctd colspan=\"5\"\u003e(*\u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.05)\u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tfoot\u003e\n \u003c/table\u003e\n\u003c/div\u003e\n\u003cp\u003e\u003c/p\u003e\n\u003ctable border=\"1\" id=\"Tab2\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eICSI and R-ICSI embryo in SVBT cycles\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\u0026nbsp;\u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eR-ICSI\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eICSI\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e\u0026chi;\u003csup\u003e2\u003c/sup\u003e\u003cem\u003e/ t\u003c/em\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e\u003cem\u003eP\u003c/em\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eFET blastocyst cycle\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e142\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e164\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003ctd align=\"left\"\u003e\u0026nbsp;\u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003ePatient age (years)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e29.1\u0026thinsp;\u0026plusmn;\u0026thinsp;3.3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e28.9\u0026thinsp;\u0026plusmn;\u0026thinsp;3.0\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.490\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.138\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003einfertility duration (years)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3.5\u0026thinsp;\u0026plusmn;\u0026thinsp;2.7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3.4\u0026thinsp;\u0026plusmn;\u0026thinsp;2.4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.141\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.255\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eBMI(kg/m2)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e23.4\u0026thinsp;\u0026plusmn;\u0026thinsp;3.9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e23.2\u0026thinsp;\u0026plusmn;\u0026thinsp;3.8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.774\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.078\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eClinical pregnancy rate (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e68.3\u003c/p\u003e\n \u003cp\u003e(97/142)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e68.3\u003c/p\u003e\n \u003cp\u003e(112/164)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.000\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.000\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eImplantation rate (%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e70.4\u003c/p\u003e\n \u003cp\u003e(100/142)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e70.1\u003c/p\u003e\n \u003cp\u003e(115/164)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.003\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.954\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eectopic pregnancy(%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.0\u003c/p\u003e\n \u003cp\u003e(1/97)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e0\u003c/p\u003e\n \u003cp\u003e(0/112)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.160\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.281\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eAbortion rate(%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e17.5\u003c/p\u003e\n \u003cp\u003e(17/97)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e17.9\u003c/p\u003e\n \u003cp\u003e(20/112)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.004\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.950\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eSex ratio\u003c/p\u003e\n \u003cp\u003e(male/female)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.45\u003c/p\u003e\n \u003cp\u003e(48/33)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1.19\u003c/p\u003e\n \u003cp\u003e(51/43)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.443\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.505\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003eLive birth rate(%)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e57.0\u003c/p\u003e\n \u003cp\u003e(81/142)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e57.3\u003c/p\u003e\n \u003cp\u003e(94/164)\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.002\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e0.961\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n\u003c/table\u003e\n\u003cp\u003e\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003ePrevious pregnancy history, duration of infertility, forward-moving sperm counts, and abnormal sperm rate have significance to predict fertilization failure, so whether a patient should conduct short-time insemination should based on the above indexes (Guo et al. \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2012\u003c/span\u003e). During the procedures of short co-incubation, patients presented a less than 30% fertilization rate and underwent early R-ICSI treatment. Early R-ICSI was carried out to reduce the occurrence of total fertilization failure (TFF) and near-total fertilization failure (NFF) (Paffoni et al. \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). The incidence of NFF was 6.49% (864/13,317), whereas that of TFF was 4.21% (561/13,317)(Zeng et al. \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2022\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eWhen is the right time to perform R-ICSI that can achieve a better outcome (Zeng et al. \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2022\u003c/span\u003e)? For the second polar body at more or less 6 h, performing R-ICSI after 6 h of coincubation can salvage cases with fertilization failure in IVF. The higher fertilization rate of R-ICSI indicates that all oocytes without signs of fertilization after 6 h of coincubation should undergo R-ICSI (Shiraiwa et al. \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e2021\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eHowever, the effectiveness of early R-ICSI remains debatable. In the study of the sibling eggs were divided into conventional insemination and short insemination combined with R-ICSI if required. There were 11 cycles in which R-ICSI was performed due to TFF occurring in the eggs with the short insemination. While in 6 of these cycles, fertilization occurred in the patient's eggs in the 20 h insemination group (Liu et al. \u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e2016\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eAlthough the early cumulus cell removal alone (4 h) had similar pregnancy outcomes compared with conventional cumulus cell removal after 20 hours of insemination (Kong et al. \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). However, the pregnancy outcomes of R-ICSI embryos in fresh cycles remains controversial. Zeng J et al. showed that the R-ICSI embryos had lower rates of implantation than the ICSI embryos in fresh embryo transfer. Whereas Jiang L et al. showed that rates of implantation, clinical pregnancy, and live birth were similar in the early R-ICSI and ICSI groups(Jiang et al. \u003cspan citationid=\"CR4\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). (The reason maybe they did not emphasize all transfer embryo origin from R-ICSI, and the cases is small, only 7 cycles were included.) And the the pregnancy outcomes of R-ICSI and ICSI embryos in FET cycles is less reported.\u003c/p\u003e \u003cp\u003eIn this study, we selected primary infertility patients with age\u0026thinsp;\u0026le;\u0026thinsp;35 years and \u0026ge;\u0026thinsp;5 oocytes in their first Re-ICSI/ICSI cycle to minimize the influence of age and oocytes factor. In the early R-ICSI cycles, especially part of oocytes R-ICSI cycles, the embryos come from short-term insemination embryos and R-ICSI embryos together(Zeng et al. \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2022\u003c/span\u003e). In this study, the embryos transferred all from R-ICSI fertilizaion.\u003c/p\u003e \u003cp\u003eWe choose D3 two high quality embryos in the first fresh cleavage-stage ET cycles, or SVBT (all embryo frozen) with D5 high quality blastocyst in their first FET cycle to reduce the effects of embryo and ET frequency. Another reason for choosing D5 blastocysts with high quality is that they have a 100% survival rate in the SVBT cycle.\u003c/p\u003e \u003cp\u003eOur study showed that the R-ICSI embryos clinical pregnancy rate, implantation rate and live birth rate were lower than the ICSI embryos in fresh embryo transfer. Whereas there were no significant difference between R-ICSI and ICSI embryos in the FET cycle.\u003c/p\u003e \u003cp\u003eThere were two differences in R-ICSI/ICSI groups, one is dispersing the cumulus cells method, another is fertilization time. In the R-ICSI group, the sperms were micro-injected into oocytes 4\u0026ndash;6 h later compared with those in the ICSI group. The differences of pregnancy outcomes of R-ICSI/ICSI probably because of the oocyte aging and subsequent embryonic development(Zeng et al. \u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e2022\u003c/span\u003e).\u003c/p\u003e \u003cp\u003eWhereas from the results of our study, we know that R-ICSI/ICSI embryo had similar pregnancy outcomes in FET cycle. This certificated that R-ICSI/ICSI embryo had similar competent of development. The lower pregnancy outcomes of R-ICSI embryo in fresh ET cycle probably because the fertilization time 4\u0026ndash;6 h later than ICSI, leading to asynchronized endometrium.\u003c/p\u003e \u003cp\u003eWe know that late R-ICSI (18\u0026ndash;20 h) lead to poor clinical pregnancy outcome resulting from oocyte aging (Lombardi et al. 2003) and asynchronization between endometrial growth and embryo development (Sermondade et al. 2021). However, frozen embryo transfer seemed to improve with pregnancy rates and implantation rate in late R-ICSI patients(Paffoni et al. \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). The strategy of cryopreservation could overcome the loss of synchronization between endometrial growth and late R-ICSI embryo development (Paffoni et al. \u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e2021\u003c/span\u003e). In early R-ICSI cycles, unfertilized oocytes by ICSI only 6h later instead of nearly 1-day-old in late R-ICSI. So the influences of oocyte aging and asynchronization between endometrial growth and embryo development was minor compared with late R-ICSI. But the results of our study about embryos from early R-ICSI were similar with late R-ICSI.\u003c/p\u003e \u003cp\u003eIn consideration of fresh cleavage-stage ET cycles could make negative effects on the clinical outcomes after R-ICSI. In early R-ICSI cycles, if a patient had both IVF and R-ICSI embryos, IVF embryos should be preferred in fresh ET with the same embryo score, while R-ICSI embryos preferred to cryopreservation.\u003c/p\u003e \u003cp\u003eThe limitation of the study was not distinguish the R-ICSI embryo according the micro-injecting time.\u003c/p\u003e \u003cp\u003eIn conclusion, our results clearly show that early R-ICSI combined with frozen embryo transfer could achieve satisfying clinical outcomes compared with fresh embryo transfers. Therefore, the strategy of cryopreservation could overcome the technical and biological issues of the loss of synchronization between endometrial growth and embryo development associated with R-ICSI.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eEthics approval and consent to participate\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe Fourth Hospital of Shijiazhuang Ethics Committee approved this study (approval no. 20220049). Informed consent was obtained from all subjects. The procedures used in this study adhered to the tenets of the Declaration of Helsinki. All experiments were performed in accordance with relevant guidelines and regulations.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConsent for publication\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe datasets used during the present study are available from the corresponding author upon reasonable request.\u0026nbsp;Data will be made available to the editors of the journal for review or query upon request.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll authors declare no conflict of interest.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eHebei Province Medical Science Research Key Project（20231650）\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026apos; contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eYAN JIANG, XIAO-HUA WU and JING-CHUAN YUAN wrote the main manuscript text. GE SONG, XU-HUI ZHANG and SUI-BING MIAO prepared table 1-2. and figures 1. All authors reviewed the manuscript.\u0026nbsp;All authors read and approved the manuscript and agree to be accountable for all aspects of the research in ensuring that the accuracy or integrity of any part of the work are appropriately investigated and resolved.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026apos; information (optional)\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\u003cli\u003e\u003cspan\u003eGardner DK, Schoolcraft WB. (1999) Culture and transfer of human blastocysts. Curr Opin Obstet Gynecol 11(3): 307\u0026ndash;311.doi: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1097/00001703-199906000-00013\u003c/span\u003e\u003cspan address=\"10.1097/00001703-199906000-00013\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. PMID: 10369209.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eGuo H, Yang J, Zhang C, Li H, Yin B, Gu B, Xie J, He Q. (2012) Analysis of clinical data of patients with different outcomes after short-time insemination. Andrologia. 44 Suppl 1:667 \u0026ndash; 71. doi: \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1111/j.1439-0272.2011.01247.x\u003c/span\u003e\u003cspan address=\"10.1111/j.1439-0272.2011.01247.x\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. Epub 2011 Dec 2. PMID: 22136561.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eHe Y, Liu H, Zheng H, Li L, Fu X, Liu J. Effect of early cumulus cells removal and early rescue ICSI on pregnancy outcomes in high-risk patients of fertilization failure. Gynecol Endocrinol. 2018;34(8):689\u0026ndash;93. Epub 2018 Feb 15. PMID: 29448847.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJiang L, Qian Y, Chen X, Ji X, Ou S, Li R, Yang D, Li Y. Effect of early rescue ICSI and split IVF-ICSI in preventing low fertilization rate during the first ART cycle: A real-world retrospective cohort study. Reprod Med Biol. 2021;27(1):e12420. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1002/rmb2.12420\u003c/span\u003e\u003cspan address=\"10.1002/rmb2.12420\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. PMID: 34934401; PMCID: PMC8656193.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJiang Y, Cao Q, Zhao X, Li L, Li S, Gao F. Percutaneous epididymal sperm aspiration and short time insemination in the treatment of men with obstructive azoospermia. J Assist Reprod Genet. 2013;30(9):1175\u0026ndash;9. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s10815-013-0075-1\u003c/span\u003e\u003cspan address=\"10.1007/s10815-013-0075-1\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. Epub 2013 Aug 29. PMID: 23989999; PMCID: PMC3800539.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eJiang Y, Song G, Zhang XH, Miao SB, Wu XH. Frozen blastocysts: Assessing the importance of day 5/day 6 blastocysts or blastocyst quality. Exp Ther Med. 2022;23(5):333. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.3892/etm.2022.11262\u003c/span\u003e\u003cspan address=\"10.3892/etm.2022.11262\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. Epub 2022 Mar 16. PMID: 35401807; PMCID: PMC8987946.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eKong P, Yin M, Tang C, Zhu X, Bukulmez O, Chen M, Teng X. Effects of early cumulus cell removal on treatment outcomes in patients undergoing in vitro fertilization: A retrospective cohort study. Front Endocrinol (Lausanne). 2021;12:669507. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.3389/fendo.2021.669507\u003c/span\u003e\u003cspan address=\"10.3389/fendo.2021.669507\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. PMID: 34025582; PMCID: PMC8138552.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLiu J, Zhang X, Yang Y, Zhao J, Hao D, Zhang J, Liu Y, Wu W, Wang X. Long-time vs. short-time insemination of sibling eggs. Exp Ther Med. 2016;12(6):3756\u0026ndash;60. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.3892/etm.2016.3827\u003c/span\u003e\u003cspan address=\"10.3892/etm.2016.3827\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. Epub 2016 Oct 20. PMID: 28105107; PMCID: PMC5228384.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eLombardi E. Live birth and normal 1-year follow-up of a baby born after transfer of cryopreserved embryos from rescue intracytoplasmic sperm injection of 1-day-old oocytes. Fertil Steril. 2003;80:646\u0026ndash;8. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/S0015-0282(03)00996-8\u003c/span\u003e\u003cspan address=\"10.1016/S0015-0282(03)00996-8\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003ePaffoni A, Reschini M, Pisaturo V, Guarneri C, Palini S, Vigan\u0026ograve; P. Should rescue ICSI be re-evaluated considering the deferred transfer of cryopreserved embryos in in-vitro fertilization cycles? A systematic review and meta-analysis. Reprod Biol Endocrinol. 2021;4(1):121. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1186/s12958-021-00784-3\u003c/span\u003e\u003cspan address=\"10.1186/s12958-021-00784-3\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. PMID: 34348713; PMCID: PMC8336078.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eSermondade N, Hugues J, Cedrin-Durnerin I, Poncelet C, Benzacken B, L\u0026eacute;vy R, Sifer C. Should all embryos from day 1 rescue intracytoplasmic sperm injection be transferred during frozen\u0026ndash;thawed cycles? Fertil Steril. 2010;94:1157\u0026ndash;8. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://doi.org/10.1016/j.fertnstert.2009.12.001\u003c/span\u003e\u003cspan address=\"10.1016/j.fertnstert.2009.12.001\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eShiraiwa Y, Enatsu N, Yamagami K, Furuhashi K, Iwasaki T, Otsuki J, Shiotani M. Clinical Outcomes of Rescue Intracytoplasmic Sperm Injection at Different Timings Following In Vitro Fertilization. J Reprod Infertil. 2021;22(4):251\u0026ndash;7. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.18502/jri.v22i4.7650\u003c/span\u003e\u003cspan address=\"10.18502/jri.v22i4.7650\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. PMID: 34987986; PMCID: PMC8669413.\u003c/span\u003e\u003c/li\u003e \u003cli\u003e\u003cspan\u003eZeng J, Yao Z, Zhang Y, Tian F, Liao T, Wu L, Li Y. Fertilization and neonatal outcomes after early rescue intracytoplasmic sperm injection: a retrospective analysis of 16,769 patients. Arch Gynecol Obstet. 2022;306(1):249\u0026ndash;58. \u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003e10.1007/s00404-022-06445-z\u003c/span\u003e\u003cspan address=\"10.1007/s00404-022-06445-z\" targettype=\"DOI\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e. Epub 2022 Apr 5. PMID: 35380279; PMCID: PMC9300487.\u003c/span\u003e\u003c/li\u003e\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Total fertilization failure, early-rescue ICSI, frozen embryo transfer, clinical outcomes","lastPublishedDoi":"10.21203/rs.3.rs-2596943/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-2596943/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cstrong\u003eContext: \u003c/strong\u003eEarly-rescue intracytoplasmic sperm injection (R-ICSI) can avoid total fertilization failure in conventional in vitro fertilization (IVF). However, the R-ICSI embryos had lower implantation rate than the direct ICSI in the fresh embryo transfer.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAims:\u003c/strong\u003e To investigate the effect of frozen embryo transfer (FET)after R-ICSI.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eMethods\u003c/strong\u003e: This was a retrospective study of the first cycle primary infertility patients with the age ≤ 35 undergoing R-ICSI and ICSI treatment. The clinical pregnancy rate, implantation rate, ectopic pregnancy, abortion rate and live birth rate were analyzed between the R-ICSI and ICSI groups in their first embryo transfer (fresh and FET cycles).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eKey Results\u003c/strong\u003e: The average age of patients in fresh and frozen ET of two groups was (29.1±3.1 vs. 29.0±3.2, and 28.9±3.0 vs. 29.1±3.3), respectively (\u003cem\u003eP\u0026gt;\u003c/em\u003e0.05). The R-ICSI embryos clinical pregnancy rate, implantation rate and live birth rate were lower than the ICSI embryos in fresh embryo transfer. Whereas there were no significant difference between R-ICSI and ICSI embryos in the FET cycle.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConclusions: \u003c/strong\u003eR-ICSI embryos with frozen embryo transfer would be an optimal strategy rather than fresh embryo transfers.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eImplications:\u003c/strong\u003eearly R-ICSI combined with frozen embryo transfer could achieve satisfying clinical outcomes compared with fresh embryo transfers.\u003c/p\u003e","manuscriptTitle":"Comparing the pregnancy outcomes of fresh and frozen embryo transfer after early rescue ICSI","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2023-03-10 00:00:25","doi":"10.21203/rs.3.rs-2596943/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"f3ede440-be6c-412d-b632-4feb3680cd97","owner":[],"postedDate":"March 10th, 2023","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[],"tags":[],"updatedAt":"2023-03-22T14:45:01+00:00","versionOfRecord":[],"versionCreatedAt":"2023-03-10 00:00:25","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-2596943","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-2596943","identity":"rs-2596943","version":["v1"]},"buildId":"WrCJVZZCHTDjtuVLN7oU0","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}