{"paper_id":"55bf3a86-e2e5-49f6-b0c8-ac9d404d57fe","body_text":"Since the introduction of assisted reproductive technology\n(ART), in vitro fertilization (IVF) has enabled\ncountless couples to achieve pregnancy. However,\nfailure to conceive after multiple attempts with different\nmethods imparts a significant emotional and financial\nburden on patients ( 1 - 4 ). It has been estimated\nthat up to 85% of embryos do not implant ( 5 ,  6 ). Many\nattempts have been made to identify factors that can\npredict the success of IVF and it is generally accepted\nthat female age, duration of subfertility, baseline follicle\nstimulating hormone (FSH) levels, and number\nof oocytes are predictors of pregnancy after IVF ( 7 ,\n 8 ). In our prior study, we have identified that the number\nof embryos transferred, the presence of ovarian\nhyperstimulation syndrome, female infertility factors\nother than tubal factors, and embryo quality were correlated\nwith the failure to achieve birth emphasizing a\nsuccessful singleton at term (BESST) (i.e., the singleton,\nterm gestation and live birth) ( 9 ,  10 ). Other studies\nhave shown that IVF success is associated with the\ndiagnosis after an infertility workup, the number of\nprevious unsuccessful IVF attempts, and a prior successful\npregnancy; however, no truly useful model for\npredicting the success of IVF exists ( 11 ).\nDepending on the reasons for infertility in a particular\ncouple, numerous techniques such as intracytoplasmic\nsperm injection (ICSI) and assisted hatching\n(AH) have been developed to increase the probability\nof pregnancy and a live birth ( 5 ,  12 ,  13 ). ICSI is\ntypically used for male factor infertility and in cases\nwhere eggs cannot easily be penetrated by sperm.\nDespite the concern for genetic abnormalities, it is a\nproven technique for achieving successful pregnancy\nand live birth ( 14 ,  15 ). It is well known that a proportion\nof euploid embryos fail to implant because of\nhatching difficulties ( 15 ) and AH involves artificial\ndisruption of the zona pellucida with the intent of increasing\nimplantation potential ( 16 ). Many methods\nhave been developed to disrupt the zona pellucida and\nlaser AH (LAH) has been found to be more effective\nin some subgroups of patients ( 12 ,  17 ). However, a\nrecent analysis by Myers et al. ( 18 ) has concluded that\nthere is relatively little high-quality evidence to support\nthe choice of specific interventions.\nThe purpose of this study was to determine the\nassociation of factors that affected the clinical pregnancy\nand live birth rates in patients that underwent\nIVF who received both ICSI and LAH, neither ICSI\nor LAH, or only ICSI or LAH.\n\nIn this retrospective cohort study the outcomes of\nwomen who underwent IVF with or without ICSI at\nthe Far Eastern Memorial Hospital, Taipei, Taiwan\nbetween January 2007 and December 2010 were\nreviewed. Cases in which estradiol levels exceeded\n50 pg/mL on the second day of the menstrual cycle\nwere excluded. The study was approved by the Research\nEthics Review Committee of the Far Eastern\nMemorial Hospital. Due to the retrospective nature of\nthe study the requirement for informed consent was\nwaived.\nCauses of reduced female fertility included tubal\ncauses, endometriosis, anovulation, polycystic ovary\nsyndrome (PCOS), decreased ovarian reserve, uterine\ndisorders, age >35 years (advanced maternal age) and\nunidentified reasons. Females might have had one or\nmultiple factors. Male causes of infertility were decreased\nsperm concentration (<2×10 7 /ml), decreased\nsperm motility (<50%) and azoospermia. Patients\nwith one or more of the following criteria underwent\nICSI: 1. fertilization rate below 50% in a prior IVF\nattempt and 2. male factor infertility. In cases of azoospermia,\nsperm for ICSI was obtained by microsurgical\nepididymis sperm aspiration (MES) or testicular\nsperm extraction (TESE). Patients with one or more\nof the following criteria underwent LAH: 1. zona pellucida\n>15 μm, 2. maternal age over 38 years and 3. at\nleast three failed IVF attempts.\nLAH was performed in a standard manner. Briefly,\na 1.48 μm infrared diode laser (OCTAX Laser Shot™\nSystem, Medical Technology Vertriebs-GmbH, Germany)\nin a computer-controlled non-contact mode\nwas used. After positioning the embryo, the laser was\nfocused at the equatorial level of the zona pellucida. A\npulse length of 2.8 ms was used and the LAH procedure\nwas performed until 25% of the zona pellucida\nwas drilled.\nThe method of ovulation induction used in the\nstudy center was previously published ( 9 ). In brief,\ngonadotropin-releasing hormone agonist (Supremon,\nAventis Pharma Deutschland, Frankfurt, Germany)\nwas administered from the third day of the menstrual\ncycle via nasal spray, daily, in 4 doses of 200 μg. FSH\n(Gona-F, Serono, Geneva, Switzerland), 150-225 IU,\nwas administered daily from the fifth day of the menstrual\ncycle via subcutaneous injection into the abdomen.\nLuteinizing hormone (LH) and estradiol levels\nwere measured from the seventh day of the cycle, and\ntransvaginal ultrasonography was performed every two days in order to adjust dosages until complete follicular\ngrowth was achieved. When appropriate follicular\ngrowth was detected, 10000 IU of human chorionic\ngonadotropin (hCG, Pregnyl, NV Organon, Oss,\nThe Netherlands) was injected and oocyte retrieval\nwas performed 35 hours later. At four hours after oocyte\nretrieval, IVF was carried out, with or without\nICSI. Two to five days later, embryos at the 4-cell to\nblastocyst stage were transferred; the remainder were\nfrozen and stored in liquid nitrogen.\nPregnancy was defined as a βhCG level greater than\n50 mIU/mL 14 days after day 2 embryo transfer (ET).\nClinical pregnancy was defined by the ultrasound\nobservation of fetal cardiac activity. We defined live\nbirth as the birth of a newborn, irrespective of the duration\nof gestation that exhibited any signs of life.\nFor analysis, patients were divided into four groups:\n1. those that did not receive either ICSI or LAH, 2.\nthose that received ICSI only, 3. those that received\nLAH only and 4. those that received both ICSI and\nLAH.\nFor comparability among the four groups we used\none-way analysis of variance (ANOVA) for normally\ndistributed continuous variables and the chi-square\ntest for categorical variables. If the data was nonnormally\ndistributed, Kruskal-Wallis tests were used\nto determine the difference among the four groups.\nWhen significance among group differences were\napparent, multiple comparisons of means were performed\nusing the Bonferroni procedure with type-I error\nadjustment. Parametric variables were represented\nas mean and standard deviation (SD) and categorical\ndata were represented by number (n) and percentage\n(%). Nonparametric variables were represented as\nmedian (inter-quartile range). Univariate logistic regression\nanalysis was performed to analyze the odds\nratio (OR) of significant factors associated with successful\npregnancy and live birth. Variables having a p\nvalue <0.05 in the univariate analysis were selected\nand evaluated by multivariate logistic regression models\nwith the conditional forward selection method. All\nstatistic assessments were two-sided and evaluated at\nthe 0.05 level of significance. Statistic analyses were\nperformed using SPSS 15.0 statistics software (SPSS\nInc., Chicago, IL, USA).\n\nAfter applying the inclusion and exclusion criteria,\na total of 375 women who underwent IVF between\nJanuary 2007 and December 2010 were included in\nthe analysis. The mean age of patients was 34.1±4.7\nyears, and the mean age of their partners was 37.3 ±\n5.4 years. In total, 121 patients (32.2%) did not receive\neither ICSI or LAH, 176 patients (46.9%) received\nICSI only, 22 patients (5.9%) had LAH only, and\n56 patients (14.9%) underwent both ICSI and LAH.\nThe demographic and clinical characteristics of the\npatients are shown in  table 1 . There were significant\ndifferences in the age of partners, age of the patients,\nduration of infertility, the reason for infertility (tubal\nfactor, other female factors, and male factor), number\nof previous IVF courses, oocyte number, and embryo\nnumber among the four groups (p<0.05).\nIn total, 179 (47.7%) women became pregnant. Of\nthese, 126 (33.6%) had subsequent live births. The\nresults of the univariate and multivariate analyses\nfor factors that affected clinical pregnancy rate are\nshown in tables  2  and  3 , respectively. Multivariate\nlogistic regression indicated that only advanced maternal\nage affected clinical pregnancy rate in those that\ndid not receive either ICSI or LAH (OR=0.87, 95%\nCI: 0.78 to 0.96, p=0.005). In patients that received\nICSI only, advanced maternal age (OR=0.93, 95%\nCI: 0.86 to 0.99, p=0.044), female factors other than\ntubal (OR=3.37, 95% CI: 1.26 to 19.05, p=0.016)\nand embryo number (OR: 1.10, 95% CI: 1.03 to 1.18,\np=0.007) affected the clinical pregnancy rate. In patients\nthat received LAH only, only embryo number\n(OR=3.26, 95% CI: 1.24 to 8.57, p=0.017) affected\nthe clinical pregnancy rate. In those that received both\nICSI and LAH, only male factor (OR=0.32, 95% CI:\n0.11 to 0.97, p=0.044) affected the clinical pregnancy\nrate.\nThe results of univariate and multivariate analyses\nof factors influencing the live birth rate are shown\nin tables  4  and  5 , respectively. Multivariate logistic\nregression analysis indicated that oocyte number\n(OR=1.07, 95% CI: 1.01 to 1.13, p=0.031) affected\nthe live birth rate in patients that did not receive either\nICSI or LAH. In patients that received ICSI only, advanced\nmaternal age (OR=0.89, 95% CI: 0.82 to 0.96,\np=0.004) and ET number (OR=1.59, 95% CI:1.05 to\n2.418, p=0.027) affected the live birth rate. In patients\nthat received both ICSI and LAH, female factors other\nthan tubal affected the live birth rate (OR=5.92, 95%\nCI:1.14 to 30.73, p=0.016). No factors were found to\naffect the live birth rate in patients that received LAH\nonly.\nPatient demographic clinical characteristics (n=375)\nET; Embryo transfer, ICSI; Intracytoplasmic sperm injection, IVF; In vitro fertilization, LAH; Laser assisted hatching, PCOS; Polycystic ovary\nsyndrome, *; Indicates a significant difference,p<0.05, †; Indicates a statistically significant difference between the indicated group and\nthe group that did not receive ICSI or LAH group, ‡; Indicates a statistically significant difference between the indicated group and the ICSI\ngroup, §; Indicates a statistically significant difference between the LAH and both ICSI and LAH groups, p values are based on 1; ANOVA,\n2; Kruskal-Wallis test and 3; Chi-square test.\nData are presented as mean±standard deviation, number (percentage), or median (interquartile range).\nPair-wise multiple comparisons between groups were determined using Bonferroni’s test with α=0.008 adjustment.\nResults of univariate analysis for factors that affected clinical pregnancy rates in the four groups\nCI; Confidence interval, ET; Embryo transfer, ICSI; Intracytoplasmic sperm injection, IVF; In vitro fertilization, LAH; Laser assisted hatching,\nOR; Odds ratio and *; Significance: p<0.05.\nResults of multivariate analysis for factors that affected clinical pregnancy rates in the four groups\nCI; Confidence interval, ICSI; Intracytoplasmic sperm injection, IVF; In vitro fertilization, LAH; Laser assisted, OR; Odds ratio and *; Significance:\np<0.05.\nResults of univariate analysis for factors that affected live birth rate in the four groups\nCI; Confidence interval, ET; Embryo transfer, ICSI; Intracytoplasmic sperm injection, IVF; In vitro fertilization, LAH; Laser assisted hatching,\nOR; Odds ratio and *; Significance: p<0.05.\nResults of multivariate analysis for factors that affected live birth rate in the four groups\nCI; Confidence interval, ET; Embryo transfer, ICSI; Intracytoplasmic sperm injection, IVF; In vitro fertilization, LAH; Laser assisted hatching,\nOR; Odds ratio and *; Significance p<0.05.\n\nThe results of this study showed that different\nfactors affected the clinical pregnancy rate and live\nbirth rate in patients who underwent IVF that received\nICSI and LAH, neither ICSI or LAH, and\nICSI or LAH only. In patients that received LAH\nonly, only embryo number (OR=3.26, 95% CI:\n1.24 to 8.57, p=0.017) affected the clinical pregnancy\nrate, and in those that received both ICSI\nand LAH only male factor (OR=0.32, 95% CI:\n0.11 to 0.97, p=0.044) affected the clinical pregnancy\nrate. Furthermore, in patients that received\nonly ICSI, advanced maternal age was associated\nwith a decreased chance and ET number with an\nincreased chance of live births; in patients that did\nnot receive either ICSI or LAH oocyte number was\nassociated with an increased chance of live birth.\nNumerous attempts have been made to develop\nmodels that predict the success or failure of IVF,\nthough few have been shown to be successful ( 11 ).\nWhile studies have clearly indicated that factors\nsuch as female age and baseline FSH levels are\npredictive of pregnancy after IVF, it remains difficult\nfor physicians to advise patients on how to\nproceed after an IVF failure.\nICSI is commonly used to treat male factor infertility\nand in cases where the sperm cannot\npenetrate the egg. We have found that in patients\nthat received only ICSI, only ET number was associated\nwith an increased chance of having a\nlive birth. Though ICSI has increased pregnancy\nand live birth rates in patients undergoing IVF,\nconcerns remain regarding chromosomal abnormalities\nand some authors consider the procedure\nover used ( 19 ,  20 ). Tan et al. ( 21 ) compared the\noutcomes of IVF-ET (IVF) and ICSI in non-male\ninfertility patients with low numbers of oocytes retrieved\nand reported that the rates of fertilization,\nnormal fertilization, complete fertilization failure,\ncleavage, good embryo, implantation, and clinical\npregnancy did not differ between the groups. The\nauthors concluded that ICSI did not improve clinical\noutcomes in non-male infertility patients with\na low number of oocytes retrieved. Hodes-Wertz\net al. ( 22 ) studied the use of ICSI in couples who\npreviously underwent ICSI at another institution\nand found that stringent criteria for ICSI did not\ncompromise clinical outcomes and concluded that\nICSI was over used.\nWe found that LAH alone was not associated\nwith an increased live birth rate, but that the use\nof both ICSI and LAH was associated with an increased\nlive birth rate in cases when female infertility\nfactors other than tubal were not present. While\nAH and LAH are commonly used, a recent review\nby Hammadeh et al. ( 16 ) observed that routine use\nof AH was not appropriate as no evidence of a universal\nbenefit existed and the procedure was not\nwithout potential risks. Ali et al. ( 17 ) reported that\nLAH was beneficial for women .36 years of age,\nembryos with a thin zona (.16 ƒÊm), and for those\nwith repeated IVF failures. It was not beneficial\nfor women .37 years of age or in cases in which\nthe zona was .17 ƒÊm. Mansour et al. ( 23 ) reported\na benefit of AH in patients with a poor prognosis\nsuch as those with two or more failed IVF cycles,\npoor embryo quality, and women >38 years of age.\nPetersen et al. ( 24 ) reported that for patients with\nrepeated implantation failures, the implantation\nrate in those who received laser-thinned embryos\nwas significantly higher (10.9%) than in those\nwhose embryos were not laser-thinned (2.6%).\nThis difference, however, was not seen in patients\nwith only one previous implantation failure. A recent\nsystematic review by Carney et al. ( 25 ) examined\nthe effectiveness of AH and concluded\nthat the increased chance of achieving a clinical\npregnancy by AH only just reached statistical significance.\nThe data did not support an increase in\nlive birth rate. In our study, LAH did not increase\nthe pregnancy or live birth rates. However, in  table 3  LAH did increase the clinical pregnancy rate as\nrelated to embryo number. Combined with ICSI,\nin  table 3  the results showed that in cases where\ninfertility of the couple was caused by male factor,\nthe clinical pregnancy rate increased significantly.\nThus the use of assistance should be considered\naccording to the special circumstances of each\ncouple.\nThere are some limitations in this study that\nshould be considered. First, this was a retrospective\nstudy, with a heterogeneous patient population.\nIn addition, the numbers of patients in the\nsubgroup that received only LAH was small.\n\nThe results of this study indicate that the chance\nof a live birth in patients undergoing IVF and ICSI\nand/or LAH vary with the causes of infertility. Oocyte number, maternal age and ET number and\nfemale infertility factors other than tubal have\naffected the live birth rate in patients that did\nnot receive ICSI or LAH, those that received\nICSI only and those that received both ICSI and\nLAH, respectively. No factors affected the live\nbirth rate in patients that received LAH only.\nThese data might assist in advising patients\non the appropriateness of ICSI and LAH after\nfailed IVF.","source_license":"CC-BY-4.0","license_restricted":false}