Embryologic outcomes among patients using a microfluidics chip compared to density gradient centrifugation to process sperm: a paired analysis

Purpose To evaluate embryologic outcomes among paired IVF cycles in which a microfluidics chip was utilized compared to density gradient centrifugation for sperm processing.

This was a retrospective cohort study of 88 paired IVF cycles from patients aged 18–44 years at a university-affiliated IVF center. Fresh cycles from patients undergoing ICSI with sperm processed by a microfluidics chamber (microfluidics cycles) were compared to the same patients’ previous ICSI cycles in which sperm was processed via density gradient centrifugation (control cycles). The primary outcome was the high-quality blastulation rate.

High-quality blastulation rate per oocyte retrieved was significantly higher in the microfluidics group compared to the control group (21.1% versus 14.5%, p < 0.01) as was the blastulation rate per 2PN (42.7% versus 30.8%, p < 0.01). Fertilization rates were significantly higher in the microfluidics group. The euploidy rate per oocyte retrieved was significantly higher in the microfluidics group compared with the control group (8.5% versus 4.3%, p = 0.04), while the euploidy rate per embryo biopsied was comparable (32.6% versus 21.8%, p = 0.09). In patients with male factor infertility, the high-quality blastulation rate was similar between the control and microfluidics cycles. There was a significantly higher blastulation rate among microfluidics cycles in patients without a diagnosis of male factor infertility (p < 0.01).

In this study, several embryologic outcomes, including fertilization rate, high-quality blastulation rate, and euploidy rate, were significantly higher in the microfluidics group compared to the control group. Microfluidics sperm processing may be a way to improve embryologic outcomes.

In vitro fertilization, Microfluidics, Sperm processing, Density gradient centrifugation, Euploidy

Many factors have been shown to affect embryo development, including culture conditions, oocyte quality, and sperm quality [1–4]. Poor oocyte quality is often implicated as the main factor causing poor embryo development, particularly with advancing maternal age [5]. However, sperm factors also play an important role in determining the extent of the sperm’s contribution to embryo development; these include semen parameters such as concentration and motility as well as elements related to DNA such as sperm chromatin structure, epigenetic factors, and DNA fragmentation [3, 6–8]. Sperm preparation and selection is an important step to optimize to ensure high rates of blastocyst development during the in vitro fertilization (IVF) process. It is speculated that the centrifugation used in conventional sperm processing methods may lead to sperm DNA damage. In most modern swim-up protocols, the semen sample is centrifuged and the pellet is resuspended with bicarbonate or a pH-buffered medium. After a designated period of incubation to allow for capacitation, the motile sperm at the top of the pellet are removed and used for insemination. In density gradient centrifugation, the liquefied ejaculate is first overlaid on a column of layered higher density media and centrifuged, with cells separating within the column by density [9]. Both of these methods select for the most highly motile sperm, but require centrifugation, which can potentially damage sperm DNA [9, 10]. During intracytoplasmic sperm injection (ICSI), motile sperm that have been processed using the methods above are selected for injection according to morphological parameters. However, this method does not mimic the complex processes of selection seen in the female reproductive tract [3]. More advanced methods for choosing the highest quality sperm including intracytoplasmic morphologically selected sperm injection (IMSI) and physiologic intracytoplasmic sperm injection (PICSI), among others, have been investigated but none of these time-intensive methods has been shown to improve clinical outcomes such as clinical pregnancy rates and live birth rates [3, 11]. One of the recent advances in sperm sorting techniques includes the use of a microfluidics chamber. In this system, semen is placed into the device and motile sperm progress through branching microchannels. Immotile or dead sperm and debris are left behind, selecting for the sperm with the highest motility and normal morphology [12–14]. The individual sperm for injection can then be further selected from this group by the embryologist. This may be better than the conventional methods of semen processing as it does not require centrifugation, which may induce damage to the sperm [13]. In fact, prior studies have shown that microfluidics processing improves the motility and morphology of the sperm in the final sample with lower DNA fragmentation rates compared with conventional gradient preparation [3, 15]. This may represent a potential therapeutic option for patients with certain risk factors. Infertile men with abnormal semen parameters have been shown to have higher rates of sperm DNA fragmentation, which was correlated with higher rates of sperm aneuploidy in one small study [8]. As male partners of women with a history of recurrent pregnancy loss have a significantly higher rate of sperm DNA fragmentation compared to the partners of fertile control women, this technology may also be applied to the recurrent pregnancy loss population [16]. Additionally, the advantages of the microfluidics platform also include scalability, increased automation, and reduced processing times [3]. There are relatively few studies evaluating the effectiveness of the use of microfluidics in selection of sperm to optimize fertilization and blastocyst development [11, 17, 18]. In two prospective studies comparing embryologic and clinical outcomes of sperm sorted by microfluidics compared to the swim-up method, there was no difference in fertilization or pregnancy rates. One of these studies showed a higher mean number and quality of blastocysts in the group that used microfluidics. However, both studies were small and one included only patients with unexplained infertility [11, 17]. In a recent study, chances of obtaining a euploid embryo were similar between cycles utilizing a microfluidics system compared to cycles utilizing density gradient selection, but pregnancy rates from the transfer of those euploid embryos were improved among microfluidics cycles [18]. However, this trial was small, comprising of only 25 couples, and included only patients with recurrent failure to conceive with assisted reproductive technology (ART), indicating a poor-prognosis population. In this study, our aim is to determine whether sperm processing utilizing a particular microfluidics chip improves high-quality blastulation rate compared to those utilizing density gradient centrifugation in a population of general infertility patients. We also sought to examine differences in euploidy rates among cycles where this microfluidics chip was used to process sperm compared to those utilizing density gradient centrifugation.

Study design This was a retrospective cohort study of paired IVF cycles at a single university-affiliated IVF center. Patients aged 18–44 years between January 2014 and April 2020 were included. Fresh cycles from patients undergoing ICSI with sperm processed by a microfluidics chamber (ZyMōt Multi [850 µL] Sperm Separation Device; microfluidics cycles) were compared to the same patients’ previous ICSI cycles in which density gradient centrifugation was used to process sperm (control cycles); therefore, each patient served as their own control. Use of microfluidics in the subsequent cycle was based on physician discretion and/or IVF laboratory recommendation based on previous low fertilization rate or blastulation rate. Only one microfluidics cycle and control cycle per patient were included, with the control cycle being the most recent fresh IVF cycle prior to the cycle in which the microfluidics chamber was used. Donor oocyte cycles, cycles utilizing standard insemination, cycles utilizing sperm collected via surgical extraction, and cycles in which cleavage-stage embryos were vitrified or transferred were excluded. This study was approved by the university institutional review board (UConn Health IRB number 21X-034R-1). As the database was de-identified, a complete waiver of HIPAA authorization was granted by the IRB for this retrospective chart review. Our primary objective was to determine whether high-quality blastulation rates differed between cycles in which oocytes were injected with sperm processed via a microfluidics chamber compared to those that utilized standard sperm preparation via density gradient centrifugation. Treatment protocol IVF stimulation protocols were selected based on individual patient factors and physician preference as previously described [19, 20]. Gonadotropin dosing was also chosen based on individual patient parameters and adjusted according to patient response. When ≥ 3 follicles reached ≥ 17 mm in diameter, the patients were instructed to inject either hCG 3300–10,000 IU subcutaneously (Pregnyl, Merck, Kenilworth, NJ, USA; Novarel, Ferring Pharmaceuticals, Parsipanny, NJ, USA), GnRH agonist 1 mg (leuprolide acetate, Abbott Laboratories, Chicago, IL, USA), or a combination of the two medications for final oocyte maturation. Transvaginal ultrasound-guided oocyte retrieval was performed 35 h after trigger injection. Sperm was collected via ejaculation on the morning of oocyte retrieval or was thawed from previously frozen samples, including cycles in which donor sperm was utilized. After incubation of ejaculate at room temperature to allow for liquefaction and after sperm processing as outlined below, oocytes were fertilized using ICSI. In the microfluidics cycles, the microfluidics chamber was used according to the manufacturer’s instructions. Briefly, 850 μL of the semen sample was inserted into the inlet port of the device and 750 μL of fertilization media was inserted into the outlet port. If a frozen sperm sample was used and the volume was less than 850 μL, the sperm sample was diluted with fertilization media to reach 850 μL and then inserted into the inlet port. The device with the semen sample inside was incubated in 6% CO2 at 37 °C. After 30 min, 500 μL of the sample at the outlet port was removed from the outlet port, pipetted into a labelled test tube, and returned to the incubator until the time of ICSI. A small aliquot of the supernatant was added to approximately 10 μL of 7% polyvinylpyrrolidone (PVP) and visualized under a microscope, at which point individual sperm for ICSI were selected from this sample by the embryologist. In the control cycles utilizing density gradient centrifugation, the sample was pipetted into two tubes of 90% gradient and then centrifuged. The centrifuge pellet was then transferred into sperm wash media. The sample was then centrifuged again, and the centrifuge pellet was then underlaid with 0.5–1.0 mL of Global Fert Media. This sample was then incubated in 6% CO2 at 37 °C until the time of ICSI. The motile sperm were allowed to swim up into the supernatant until ICSI was performed. A small aliquot of the supernatant was added to approximately 10 μL of 7% polyvinylpyrrolidone (PVP) and visualized under a microscope, at which point individual sperms for ICSI were selected from this sample by the embryologist. Fertilization was confirmed on the day following oocyte retrieval via visualization of two pronuclei (2PN). Embryos were cultured to the blastocyst stage and were examined on day 5. High-quality blastocysts according to Gardner criteria (3BB or better) were either transferred, vitrified, or biopsied for preimplantation genetic testing (PGT) prior to vitrification [21]. Any embryos not transferred or vitrified on day 5 were examined again on days 6 and 7 for potential vitrification, and any embryos not meeting Gardner criteria by day 7 were discarded. Outcome measures The primary outcome was the high-quality blastulation rate, calculated as number of good-quality blastocysts created per oocyte retrieved and per fertilized oocyte (2PN). Secondary outcomes included the fertilization rate (defined as the number of embryos with 2 pronuclei visualized on the day following insemination per oocyte retrieved and per mature oocyte retrieved), and the euploidy rate (defined as the number of euploid embryos per blastocyst biopsied and per oocyte retrieved). A subgroup analysis was performed examining embryologic outcomes among those with male factor infertility as well as among those without male factor infertility. Male factor infertility was defined as an abnormality in at least one semen parameter (concentration < 15 million/mL, forward progressive motility < 32%, normal morphology < 4%, volume < 1.5 mL, or total motility < 40%) on two separate semen analyses, based on the World Health Organization (WHO) lower reference limits for semen parameters [22]. Statistical analysis Statistical analysis was performed in IBM SPSS© Statistics version 27.0 (IBM, Chicago, IL, USA). As this study included paired data from two IVF cycles for each patient, McNemar’s test was used for categorical variables, with data presented as percentage and number of cycles (n). Paired T-test or Wilcoxon signed rank test was used for continuous variables depending on how the data was distributed, with data presented as mean value ± standard error of the mean (SEM). A two-sided p-value of < 0.05 was considered statistically significant.

A total of 88 patients were included in this study, each contributing one control cycle in which density gradient centrifugation was used and one study cycle in which a microfluidics chamber was used to process sperm (Table 1). The mean interval between control cycles and microfluidics cycles was 6 months. The mean anti-Müllerian hormone (AMH) level was 2.26 ng/mL. The most common primary diagnoses were male factor infertility and unexplained infertility (30.7% and 23.9%, respectively). The majority of patients (63.6%) used a different stimulation protocol in their microfluidics cycle compared to their control cycle, and a higher proportion of patients underwent PGT in their microfluidics cycle. Table 1. | Control cycle (n = 88) | | |---|---| | Age (years) | 36.8 ± 0.4 | | Partner age (years) | 37.8 ± 0.6 | | Body mass index [BMI] (kg/m2) | 26.6 ± 0.6 | | AMH (ng/mL) | 2.26 ± 0.2 | | Diagnosis | | | Unexplained | 21/88 (23.9%) | | Anovulation/Polycystic ovarian syndrome | 5/88 (5.7%) | | Male factor | 27/88 (30.7%) | | Diminished ovarian reserve | 3/88 (3.4%) | | Tubal factor | 3/88 (3.4%) | | Endometriosis | 5/88 (5.7%) | | Recurrent pregnancy loss | 8/88 (9.1%) | | Fibroids | 21/88 (23.9%) | | Other | 14/88 (15.9%) | | Used a different stimulation protocol for microfluidics cycle | 56/88 (63.6%) | Continuous variables are presented as mean ± SEM. Rates are presented as n (%) The cycle characteristics are displayed in Table 2. The percentage of patients utilizing PGT-A, mean number of oocytes retrieved, mean number of oocytes injected, and the sperm post-processing motility were all higher in the microfluidics cycles than in the control cycles. Table 2. | Control cycle (n = 88) | Microfluidics cycle (n = 88) | p-value | | |---|---|---|---| | Utilization of PGT-A | 27/88 (30.7%) | 46/88 (52.3%) | < 0.01 | | Peak E2 (pg/mL) | 1969.2 ± 95.9 | 2094.0 ± 101.2 | 0.22 | | Number of oocytes retrieved (n) | 10.6 ± 0.6 | 12.0 ± 0.7 | 0.03 | | Number of oocytes injected (n) | 7.4 ± 0.5 | 8.6 ± 0.5 | < 0.01 | | Sperm pre-processing concentration (millions/mL) | 57.2 ± 5.1 | 69.2 ± 5.9 | 0.09 | | Sperm pre-processing total motile count (millions) | 84.0 ± 11.3 | 83.1 ± 9.4 | 0.85 | | Sperm post-processing concentration (millions/mL) | 14.4 ± 2.3 | 16.2 ± 2.5 | 0.97 | | Sperm post-processing motility (%) | 77.6 ± 3.0 | 92.8 ± 2.3 | < 0.01 | Continuous variables are presented as mean ± SEM. Rates are presented as n (%) High-quality blastulation rate per oocyte retrieved was significantly higher in the microfluidics group compared to the control group (21.1% ± 1.7 versus 14.5% ± 1.8, p < 0.01; Table 3) as was the blastulation rate per 2PN (42.7% ± 3.4 versus 30.8% ± 3.3, p < 0.01). Fertilization rates were found to be significantly higher in the microfluidics group as well. While the euploidy rate per embryo biopsied appeared higher in the microfluidics group compared to the control cycle, this difference was not significant (32.6% ± 6.8 versus 21.8% ± 7.3, p = 0.09). The euploidy rate per oocyte retrieved was significantly higher in the microfluidics group compared with the control group (8.5% ± 1.9 versus 4.3% ± 1.3, p = 0.04). Table 3. | Control cycle (n = 88) | Microfluidics cycle (n = 88) | p-value | | |---|---|---|---| | Fertilization rate per oocyte retrieved (%) | 41.0 ± 2.4 | 48.6 ± 2.3 | 0.01 | | Fertilization rate per mature oocyte injected (%) | 56.1 ± 2.9 | 66.7 ± 2.6 | < 0.01 | | Number of blastocysts created (n) | 1.5 ± 0.2 | 2.5 ± 0.2 | < 0.01 | | High-quality blastulation rate per oocyte retrieved (%) | 14.5 ± 1.8 | 21.1 ± 1.7 | < 0.01 | | High-quality blastulation rate per 2PN (%) | 30.8 ± 3.3 | 42.7 ± 3.4 | < 0.01 | | Euploidy rate per blast biopsied (%) | 21.8 ± 7.3 (n = 20) | 32.6 ± 6.8 (n = 20) | 0.09 | | Euploidy rate per oocyte retrieved (%) | 4.3 ± 1.3 (n = 20) | 8.5 ± 1.9 (n = 20) | 0.04 | All variables are presented as mean ± SEM Among the patients with male factor infertility (n = 27), fertilization rate per mature oocyte injected was significantly higher in the microfluidics cycles (p = 0.02; Fig. 1A). However, among the patients without male factor infertility (n = 61), there was no significant difference in the fertilization rate (Fig. 1B). In the patients with male factor infertility, the high-quality blastulation rate was not significantly different between the control and microfluidics cycles (n = 27), whereas there was a significantly higher blastulation rate in the microfluidics cycles among patients without a diagnosis of male factor infertility (n = 61; p < 0.01). There were no differences in euploidy rate per blastocyst biopsied among those with a diagnosis of male factor infertility (n = 5), while there was a significantly higher euploidy rate among those without a diagnosis of male factor infertility (n = 15; p = 0.03).

In this study, our aim was to determine whether the use of a microfluidics chip to process sperm had any effect on high-quality blastulation rate among patients in which sperm was processed via density gradient centrifugation in a previous IVF cycle. We found that cycles utilizing this microfluidics chip for sperm preparation did have a higher blastulation rate per oocyte retrieved and per 2PN, as well as higher fertilization rates and euploidy rates per oocyte retrieved. Therefore, sperm processing utilizing this microfluidics chip appeared to improve several of the embryologic outcomes evaluated in this study. Our findings are contrary to those of a prior prospective sibling oocyte study which showed no difference between the swim-up sperm processing group and the microfluidics groups in terms of number of fertilized oocytes and number of total or high-quality blastocysts [11]. However, the authors excluded patients with fewer good-quality embryos on day 2. This thereby removed a significant number of the poorest prognosis patients from the study and may explain why there were no differences in any of the outcomes in this study. Consistent with the findings of our trial, three studies of the microfluidics technique again showed a higher number and/or rate of high-quality embryos created after utilizing the microfluidics chip [17, 23, 24]. However, they showed no difference in fertilization rates between the two groups. In the prospective trial by Yetkinel et al., only patients with unexplained infertility were included, whereas our study included patients will all diagnoses [17]. The lack of significant findings in the Yetkinel study may have been blunted by the already good-prognosis population. The increase in fertilization rate found in our current study could have occurred because in some cases, microfluidics was recommended in the second cycle to improve blastocyst development compared to the control cycle; therefore, there may have been lower than expected mean fertilization rates in the control cycles. We found higher euploidy rates among those cycles in which microfluidics sperm processing was used which is different from the findings by Keskin et al. [24]. The higher euploidy rate in our study was mostly driven by the patients without a diagnosis of male factor infertility as seen in the subgroup analysis. The lack of significant difference in euploidy rates among those with male factor infertility could be rationalized by the small sample size of those undergoing PGT-A in this group (n = 5). While one small study by Parrella et al. did previously examine the relationship between microfluidics sperm processing and euploidy rates, only patients with recurrent implantation failure and known high sperm DNA fragmentation in the setting of unexplained infertility were included [18]. Among these poor-prognosis patients, there was no significant difference in euploidy rates, but there was an improvement in clinical outcomes including implantation rate, clinical pregnancy rate, and ongoing pregnancy rate. The discrepancy between our findings and the findings of prior studies could be explained by the different study populations in each study. We did find that euploidy rates may not be improved among those with male factor infertility, perhaps suggesting that this technology should be reserved for those without this diagnosis. Nevertheless, these findings should be interpreted with caution in view of the low sample size in the male factor subgroup. Our findings have significant implications for the choice of sperm preparation in IVF cycles. Density gradient centrifugation and the swim-up technique have been utilized worldwide for decades [10]. With higher fertilization rates, blastulation rates, and euploidy rates, as well as reduced processing times leading to the potential for large-scale implementation in the laboratory, microfluidics may well represent a move away from these standard methods that require more intensive preparation by laboratory staff. This study is strengthened by its examination of one of the largest cohorts to date examining this topic. This study also utilized patients as their own controls, limiting the between-group differences and allowing for a more direct comparison. A single center for data collection was evaluated, ensuring that laboratory protocols remained consistent over time; however, this can also be a limitation, as patient characteristics and laboratory procedures vary depending on location and program. Other limitations of this study include the retrospective and observational nature. A single microfluidics device was used at our center; therefore, these findings may not be applicable to all microfluidics chips. While outside the scope of this study, we did not evaluate sperm DNA fragmentation levels among any of the participants. This is particularly relevant as microfluidics sperm preparation is known to reduce the amount of DNA fragmentation among sperm compared to density gradient centrifugation, which may translate into improved IVF outcomes [25]. Caution must also be exercised in interpreting our results as the patients’ control cycle always preceded their microfluidics cycle, leading to certain differences and advantages in each of the cohorts. For example, the results of the control cycle could be used to alter and improve the stimulation and treatment plan for the microfluidics cycle, lending an advantage to the microfluidics group based on the chosen study design. However, a recent study did not show improvement in outcomes if the stimulation protocol is changed in a subsequent cycle, and in fact there was a slight but significant improvement in outcomes when the IVF stimulation protocol remained the same as the first protocol chosen [26]. Given that the majority (63.6%) of our patients switched IVF stimulation protocols between their control and microfluidics cycles, this should not, in fact, have been advantageous; therefore, this alteration was also unlikely to improve outcomes.

In this study, we found that several embryologic outcomes, including fertilization rate, high-quality blastulation rate, euploidy rate, and numbers of blastocysts created, were significantly improved in the microfluidics group compared to the control group. This suggests that microfluidics sperm processing may be a way to improve embryologic outcomes even among good prognosis patients, which may eventually lead to improved clinical outcomes. Future prospective studies should focus on euploidy rates and clinical outcomes among those using microfluidics sperm processing in patients that are unselected for fertility diagnosis to elucidate the optimal population for application of this technology.

We wish to thank all the physician, nursing, and embryology staff at the Center for Advanced Reproductive Services for their collaboration and support. Declarations Conflict of interest The authors declare no competing interests. Footnotes Publisher's note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

- 1.Chen M, Wong SL, Wu LL, Gordon YE, Heilbronn LK, Robker RL. Differential impacts of gonadotrophins, IVF and embryo culture on mouse blastocyst development. Reprod Biomed Online Elsevier. 2019;39:372–382. doi: 10.1016/j.rbmo.2019.02.007. [DOI] [PubMed] [Google Scholar] - 2.Choi YH, Velez IC, Macías-García B, Riera FL, Ballard CS, Hinrichs K. Effect of clinically-related factors on in vitro blastocyst development after equine ICSI. Theriogenol Elsevier. 2016;85:1289–1296. doi: 10.1016/j.theriogenology.2015.12.015. [DOI] [PubMed] [Google Scholar] - 3.Vaughan DA, Sakkas D. Sperm selection methods in the 21st century. Biol Reprod. 2019;101:1076–1082. doi: 10.1093/biolre/ioz032. [DOI] [PubMed] [Google Scholar] - 4.Balaban B, Urman B. Effect of oocyte morphology on embryo development and implantation. Reprod Biomed Online. 2006;12:608–615. doi: 10.1016/S1472-6483(10)61187-X. [DOI] [PubMed] [Google Scholar] - 5.Mikwar M, MacFarlane AJ, Marchetti F. Mechanisms of oocyte aneuploidy associated with advanced maternal age. Mutat Res Mutat Res Elsevier. 2020;785:108320. doi: 10.1016/j.mrrev.2020.108320. [DOI] [PubMed] [Google Scholar] - 6.Tomlinson M, Lewis S, Morroll D. Human Fertility an international, multidisciplinary journal dedicated to furthering research and promoting good practice Sperm quality and its relationship to natural and assisted conception: British Fertility Society Guidelines for practice. Hum Fertil. 2013;16:175–193. doi: 10.3109/14647273.2013.807522. [DOI] [PubMed] [Google Scholar] - 7.Colaco S, Sakkas D. Paternal factors contributing to embryo quality. J Assist Reprod Genet. 2018;35:1953–1968. doi: 10.1007/s10815-018-1304-4. [DOI] [PMC free article] [PubMed] [Google Scholar] - 8.Arumugam M, Prashanth Shetty D, Shetty Kadandale J, Kumari NS. Association of sperm aneuploidy frequency and DNA fragmentation index in infertile men. J Reprod Infertil. 2019;20:121–126. [PMC free article] [PubMed] [Google Scholar] - 9.Marzano G, Chiriacò MS, Primiceri E, Dell’aquila ME, Ramalho-Santos J, Zara V, et al. Sperm selection in assisted reproduction: a review of established methods and cutting-edge possibilities. Biotechnol Adv. 2019;40 [DOI] [PubMed] - 10.Henkel RR, Schill W-BB. Sperm preparation for ART. Reprod Biol Endocrinol. BioMed Central; 2003;1:1–22 [DOI] [PMC free article] [PubMed] - 11.Yalcinkaya Kalyan E, Can Celik S, Okan O, Akdeniz G, Karabulut S, Caliskan E. Does a microfluidic chip for sperm sorting have a positive add-on effect on laboratory and clinical outcomes of intracytoplasmic sperm injection cycles? A sibling oocyte study. Andrologia. 2019;51:1–6. doi: 10.1111/and.13403. [DOI] [PubMed] [Google Scholar] - 12.Parrella A, Choi D, Keating D, Rosenwaks Z, Palermo GD. A microfluidic device for selecting the most progressively motile spermatozoa yields a higher rate of euploid embryos. Fertil Steril Elsevier. 2018;110:e342. doi: 10.1016/j.fertnstert.2018.07.955. [DOI] [Google Scholar] - 13.Smith GD, Takayama S. Application of microfluidic technologies to human assisted reproduction. Mol Hum Reprod. 2017;23:257–268. doi: 10.1093/molehr/gaw076. [DOI] [PMC free article] [PubMed] [Google Scholar] - 14.Oseguera-López I, Ruiz-Díaz S, Ramos-Ibeas P, Pérez-Cerezales S. Novel techniques of sperm selection for improving IVF and ICSI outcomes. Front Cell Dev Biol. 2019;7:1–23. doi: 10.3389/fcell.2019.00298. [DOI] [PMC free article] [PubMed] [Google Scholar] - 15.Quinn MM, Jalalian L, Ribeiro S, Ona K, Demirci U, Cedars MI, et al. Microfluidic sorting selects sperm for clinical use with reduced DNA damage compared to density gradient centrifugation with swim-up in split semen samples. Hum Reprod. 2018;33:1388–1393. doi: 10.1093/humrep/dey239. [DOI] [PubMed] [Google Scholar] - 16.McQueen DB, Zhang J, Robins JC. Sperm DNA fragmentation and recurrent pregnancy loss: a systematic review and meta-analysis. Fertil Steril. 2019;112:54–60. doi: 10.1016/j.fertnstert.2019.03.003. [DOI] [PubMed] [Google Scholar] - 17.Yetkinel S, Esra, Kilicdag B, Pinar, Aytac C, Haydardedeoglu B, et al. Effects of the microfluidic chip technique in sperm selection for intracytoplasmic sperm injection for unexplained infertility: a prospective randomized controlled trial. J Assist Reprod Genet. 2019;36:403–9. doi: 10.1007/s10815-018-1375-2. [DOI] [PMC free article] [PubMed] [Google Scholar] - 18.Parrella A, Keating D, Cheung S, Xie P, Stewart JD, Rosenwaks Z, et al. A treatment approach for couples with disrupted sperm DNA integrity and recurrent ART failure. J Assist Reprod Genet. 2019;36:2057–2066. doi: 10.1007/s10815-019-01543-5. [DOI] [PMC free article] [PubMed] [Google Scholar] - 19.Diluigi AJ, Engmann L, Schmidt DW, Benadiva CA, Nulsen JC. A randomized trial of microdose leuprolide acetate protocol versus luteal phase ganirelix protocol in predicted poor responders. Fertil Steril Elsevier. 2011;95:2531–2533. doi: 10.1016/j.fertnstert.2011.01.134. [DOI] [PubMed] [Google Scholar] - 20.Johnston-Macananny EB, Diluigi AJ, Engmann LL, Maier DB, Benadiva CA, Nulsen JC. Selection of first in vitro fertilization cycle stimulation protocol for good prognosis patients gonadotropin releasing hormone antagonist versus agonist protocols. J Reprod Med Obstet Gynecol. 2011;56:12–16. [PubMed] [Google Scholar] - 21.Gardner DK, Schoolcraft WB. Culture and transfer of human blastocysts. Curr Opin Obstet Gynecol. 1999;11:307–311. doi: 10.1097/00001703-199906000-00013. [DOI] [PubMed] [Google Scholar] - 22.Cooper TG, Noonan E, Von Eckardstein S, Auger J, Gordon Baker HW, Behre HM, et al. World Health Organization reference values for human semen characteristics. Hum Reprod Update. 2010;16:231–245. doi: 10.1093/humupd/dmp048. [DOI] [PubMed] [Google Scholar] - 23.Anbari F, Ali M, Munaf A, Ahamed S, Mangoli E, Nabi A, et al. Microfluidic sperm selection yields higher sperm quality compared to conventional method in ICSI program: a pilot study. Syst Biol Reprod Med. 2021;67:137–143. doi: 10.1080/19396368.2020.1837994. [DOI] [PubMed] [Google Scholar] - 24.Keskin M, Pabuçcu EG, Arslanca T, Demirkıran ÖD, Pabuçcu R. Does microfluidic sperm sorting affect embryo euploidy rates in couples with high sperm DNA fragmentation? Reprod Sci. 2021;Published online ahead of print. [DOI] [PubMed] - 25.Pujol A, Garciá-Peiró A, Ribas-Maynou J, Lafuente R, Mataró D, Vassena R. A microfluidic sperm-sorting device reduces the proportion of sperm with double-stranded DNA fragmentation. Zygote. 2021;July:1–6. [DOI] [PubMed] - 26.Wald K, Hariton E, Morris JR, Chi EA, Jaswa EG, Cedars MI, et al. Changing stimulation protocol on repeat conventional ovarian stimulation cycles does not lead to improved laboratory outcomes. Fertil Steril Elsevier Inc. 2021;116:757–65. doi: 10.1016/j.fertnstert.2021.04.030. [DOI] [PubMed] [Google Scholar]