Trophectoderm biopsy is associated with lower risks of moderate to extreme prematurity and low birthweights: a national registry cohort study of singleton livebirths from frozen-thawed blastocyst transfers.

BACKGROUND: Trophectoderm biopsy has become the mainstay assisted reproductive technique performed for preimplantation genetic testing, accounting for 43.8% of embryo transfer cycles in the United States in 2019 alone. Despite its prevalence, data on the obstetric and perinatal outcomes post-trophectoderm biopsy remains sparse and mixed. OBJECTIVE: This study aimed to examine the risks of adverse perinatal outcomes in birthweights and prematurity after transfers of the vitrified-thawed blastocyst with trophectoderm biopsy for preimplantation genetic testing. STUDY DESIGN: This was a retrospective observational cohort study of 45,712 singleton livebirths resulting from autologous vitrified-thawed blastocyst transfer cycles with or without trophectoderm biopsy for preimplantation genetic testing, reported by participating member clinics to the Society for Assisted Reproductive Technology national registry between 2014 and 2017. Adverse perinatal outcomes of preterm births and low birthweights were analyzed. Multivariable regression analyses were performed to control for covariates. Comparing the trophectoderm biopsy (n=21,584) and no trophectoderm biopsy (n=24,128) groups, adjusted odds ratios were calculated for the outcomes of small-for-gestational-age, large-for-gestational-age, low birthweight <2500 g, very low birthweight <1500 g, extremely low birthweight <1000 g, late preterm births <37 weeks, moderate preterm births <34 weeks, and extremely preterm births <28 weeks. RESULTS: Women in the trophectoderm biopsy group were older and more likely to have prior pregnancies, deliveries, and a history of spontaneous abortions. Tobacco use, diminished ovarian reserve, and recurrent pregnancy loss were also more prevalent in the trophectoderm biopsy group. Trophectoderm biopsy was not associated with small-for-gestational-age (adjusted odds ratio, 0.97; 95% confidence interval, 0.85-1.12; P=.72) or large-for-gestational-age newborns (adjusted odds ratio, 1.10; 95% confidence interval, 0.99-1.22; P=.09). Risks of preterm births <37 weeks gestation were similar between the biopsy and nonbiopsy groups (adjusted odds ratio, 0.93; 95% confidence interval, 0.85-1.02; P=.11). Trophectoderm biopsy was associated with a significantly lower risk of low birthweight <2500 g (adjusted odds ratio, 0.80; 95% confidence interval, 0.70-0.92; P<.001), very low birthweight <1500 g (adjusted odds ratio, 0.62; 95% confidence interval, 0.46-0.83; P<.001), extremely low birthweight <1000 g (adjusted odds ratio, 0.48; 95% confidence interval, 0.31-0.74; P<.001), moderate preterm birth <34 weeks (adjusted odds ratio, 0.76; 95% confidence interval, 0.64-0.91; P=.003), and extreme preterm birth <28 weeks (adjusted odds ratio, 0.63; 95% confidence interval, 0.43-0.92; P=.02). CONCLUSION: Trophectoderm biopsy is not associated with increased risks of small-for-gestational-age, large-for-gestational-age, or late preterm birth. Risks of low birthweight, very low birthweight, and extremely low birthweight from moderate and extreme preterm births are lower after trophectoderm biopsy, possibly by selecting against confined placental mosaicism or inducing placental epigenetic changes, the mechanisms of which warrant further investigation.

Comparing reproductive outcomes between conventional in vitro fertilization and nonindicated intracytoplasmic sperm injection in autologous embryo transfer cycles: a Society for Assisted Reproductive Technology Clinic Outcome Reporting System Study.

Objective: To compare clinical outcomes between nonindicated intracytoplasmic sperm injection (ICSI) and conventional insemination. Design: Autologous cycles performed from 2014-2017 were identified, excluding frozen oocyte cycles. Outcomes were compared between conventional insemination (in vitro fertilization [IVF]) and nonindiated ICSI and analyzed separately for fresh, frozen-thawed preimplantation genetic testing (PGT) and frozen-thawed non-PGT cycles. Setting: US-based fertility clinics reporting to the Society for Assisted Reproductive Technology. Participants: A total of 187,520 patients underwent 318,930 cycles, 57,516 (18.0%) using conventional IVF and 261,414 ICSI (82.0%). Interventions: Intracytoplasmic sperm injection, with or without indications (male factor, prior fertilization failure or any PGT [2012 recommendations]/single-gene PGT [2020 recommendations]). Main Outcome Measures: Odds ratios (ORs) for live birth rates and clinical pregnancy rates were calculated after multivariable adjustment for maternal age, body mass index, infertility etiologies, prior IVF births, and number oocytes retrieved. Results: Intracytoplasmic sperm injection was indicated in 151,627 (58.0%) of cycles according to 2012 American Society for Reproductive Medicine Practice Committee recommendations, and 108,895 (41.7%) according to 2020 recommendations. In multivariable models, nonindicated ICSI among fresh cycles was associated with reduced odds of completing a blastocyst-stage transfer (OR, 0.72; 95% confidence interval [CI] [0.7, 0.75]; P<.001), resulting in reduced odds of live birth (OR, 0.80; 95% CI [0.78, 0.83]; P<.001). Among completed fresh transfers, clinical pregnancy and live birth rates were comparable between nonindicated ICSI and IVF. Nonindicated ICSI in frozen-thawed cycles with PGT and without PGT was associated with comparable live birth and clinical pregnancy rates with IVF in multivariable models. Conclusion: Nonindicated ICSI was associated with reduced blastocyst availability in fresh cycles compared with IVF, leading to lower live birth rates. Outcomes from completed transfers were clinically comparable.

Higher live birth rates are associated with a normal body mass index in preimplantation genetic testing for aneuploidy frozen embryo transfer cycles: a Society for Assisted Reproductive Technology Clinic Outcome Reporting System study.

OBJECTIVE: To determine whether body mass index (BMI) was associated with live birth in patients undergoing transfer of frozen-thawed preimplantation genetic testing for aneuploidy (PGT-A) embryos. DESIGN: Retrospective cohort study of cycles reported to the Society for Assisted Reproductive Technology Clinic Outcome Reporting System. SUBJECTS: All autologous and donor recipient PGT-A-tested cycles reported to the Society for Assisted Reproductive Technology Clinic Outcome Reporting System from 2014 to 2017. INTERVENTION(S): Body mass index. MAIN OUTCOME MEASURE(S): The primary outcome measure was the live birth rate, and the secondary outcome measures were the clinical pregnancy and biochemical pregnancy rates. Multivariable generalized additive mixed models and log-binomial models were used to model the relationship between BMI and outcome measures. RESULT(S): A total of 77,018 PGT-A cycles from 55,888 patients were analyzed. Of these cycles, 70,752 were autologous, and 6,266 were donor recipient. In autologous cycles, a statistically significant and clear nonlinear relationship was observed between the BMI and live birth rates, with the highest birth rates observed for the BMI range of 23-24.99 kg/m2. When using 23-24.99 kg/m2 as the referent, other BMI ranges demonstrated a lower probability of live birth and clinical pregnancy that continued to decrease as the BMI moved further from the reference value. Patients with a BMI of <18.5 kg/m2 had a 11% lower probability of live birth, whereas those with a BMI of ≥40 kg/m2 had a 27% lower probability than the referent. CONCLUSION(S): A normal-weight BMI range of 23-24.99 kg/m2 was associated with the highest probability of clinical pregnancy and live birth after a frozen-thawed PGT-A-tested blastocyst transfer in both autologous and donor recipient cycles. A BMI outside the range of 23-24.99 kg/m2 is likely associated with a malfunction in the implantation process, which is presumed to be related to a uterine factor and not an oocyte factor, as both autologous and donor recipient cycle outcomes were associated similarly with the BMI of the intended parent.

Obstetric and Neonatal Outcomes After Transferring More Than One Embryo in Patients With Preimplantation Genetic Testing.

OBJECTIVE: To compare obstetric and neonatal outcomes after single embryo transfer (SET) compared with multiple embryo transfer (MET) from frozen-thawed transfer cycles of embryos that underwent preimplantation genetic testing for aneuploidies (PGT-A). METHODS: We conducted a retrospective cohort study from the SART CORS (Society for Assisted Reproductive Technology Clinic Outcome Reporting System) national database. Clinical and demographic data were obtained from the SART CORS database for all autologous and donor egg frozen-thawed transfer cycles of embryos that underwent PGT-A between 2014 and 2016, after excluding cycles that used frozen oocytes, fresh embryo transfer, and transfers of embryos from more than one stimulation cycle. Multivariable linear and log-binomial regression models were used to estimate the relative and absolute difference in live-birth rate, multiple pregnancy rate, gestational age at delivery, and birth weight between SET compared with MET. RESULTS: In total, 15,638 autologous egg transfer cycles and 944 donor egg transfer cycles were analyzed. Although the live-birth rate was higher with MET compared with SET in the autologous oocyte cycles (64.7% vs 53.2%, relative risk [RR] 1.24, 95% CI, 1.20-1.28), the multiple pregnancy rate was markedly greater (46.2% vs 1.4%, RR 32.56, 95% CI, 26.55-39.92). Donor oocyte cycles showed similar trends with an increased live-birth rate (62.0% vs 49.7%, RR 1.26, 95% CI, 1.11-1.46) and multiple pregnancy rate (54.0% vs 0.8%) seen with MET compared with SET. Preterm delivery rates and rates of low birth weight were significantly higher in MET compared with SET in both autologous and donor oocyte cycles and were also higher in the subanalysis of singleton deliveries that resulted from MET compared with SET. CONCLUSION: Despite some improvement in live-birth rate, nearly half of the pregnancies that resulted from MET of embryos that underwent PGT-A were multiples. Compared with SET, MET is associated with significantly higher rates of neonatal morbidity, including preterm delivery and low birth weight. The transfer of more than one embryo that underwent PGT-A should continue to be strongly discouraged, and patients should be counseled on the significant potential for adverse outcomes.

Adherence to embryo transfer guidelines in favorable-prognosis patients aged less than 35 years using autologous oocytes and in recipients using donor oocytes: a Society for Assisted Reproductive Technology Clinic Outcome Reporting System study.

OBJECTIVE: To measure the consequences of nonadherence with the 2013 American Society for Reproductive Medicine elective single embryo transfer (eSET) guidelines for favorable-prognosis patients. DESIGN: Retrospective cohort. SETTING: In vitro fertilization clinics. PATIENT(S): A total of 28,311 fresh autologous, 2,500 frozen-thawed autologous, and 3,534 fresh oocyte-donor in vitro fertilization cycles in 2014-2016 at Society for Assisted Reproductive Technology-reporting centers. INTERVENTION(S): Patients aged <35 years or using donors aged <35 years underwent first blastocyst transfer. MAIN OUTCOME MEASURE(S): Singleton birth rate, gestational age at delivery, and birth weight were compared between the eSET and non-eSET groups using the chi-square or Fisher's exact test or t-tests. RESULT(S): Among fresh transfers, 15,643 (55%) underwent eSET. Live births after non-eSETs were less likely singletons (38.0% vs. 96.5%; adjusted relative risk [aRR], 0.56) and more likely complicated by preterm delivery (55.0% vs. 20.1%; aRR, 2.39) and low birth weight (<2,500 g) (40.1% vs. 10.6%; aRR, 3.4) compared with those after eSET. Among frozen-thawed transfers, 1,439 (58%) underwent eSET. Live births after non-eSETs were less likely singletons (41.9% vs. 95.2%; aRR, 0.69; 95% confidence interval, 0.66-0.73) and more likely complicated by preterm delivery (56.4% vs. 19.5%; aRR, 2.6; 95% confidence interval, 2.2-3.1) and low birth weight (38.0% vs. 8.9%; aRR, 3.9) compared with those after eSET. Among fresh donor oocyte transfers, 1,946 (55%) underwent eSET. Live births after non-eSETs were less likely singletons (31.3% vs. 97.3%; aRR, 0.48) and more likely complicated by preterm delivery (61.1% vs. 25.7%; aRR, 2.09) and low birth weight (44.3% vs. 11.7%; aRR, 3.39) compared with those after eSET. CONCLUSION(S): Nonadherence with transfer guidelines was associated with dramatically increased multiple pregnancies, preterm births, and low birth weights.

Early experience with universal SARS-CoV-2 testing in a New York-based reproductive endocrinology practice.

The SARS-CoV-2 pandemic peak around March 2020 led to temporary closures of most fertility clinics. Many clinics reopened but required universal SARS-CoV-2 screening. However, the rate of positive results and the necessity for such testing is unknown. We report here on early results from asingle-center academic NewYork fertility practice utilizing universal SARS-CoV-2 screening. This mixed prospective retrospective cohort included 164 patients who underwent at least one SARS-CoV-2 screening test for fertility treatment between May and July2020. Patients completed 1 to 3 nasopharyngeal SARS-CoV-2 tests per cycle and remained symptom-free to continue fertility treatments. SARS-CoV-2 test results, past results, history of Covid-19 infection, and patient/cycle characteristics were recorded and tabulated through October2020. Outcomes included positive SARS-CoV-2 RNA tests, rate of prior Covid-19 infections, and clinical courses of patients testing positive. Patients underwent 263 cycles entailing 460 total SARS-CoV-2 screening tests. Fifteen patients reported astrong prior clinical history of Covid-19. Six patients experienced apositive SARS-CoV-2 test (2.3% of all cycles). Among 77 cycles (n = 58 patients) entailing one SARS-CoV-2 test, 2 cases (2.6%) were noted. Among 173 cycles (n = 121 patients) entailing two SARS-CoV-2 tests, 4 cycles (2.3%) were noted. Zero (0%) of 13 cycles (n = 13 patients) entailing 3 SARS-CoV-2 tests were positive. All patients were cleared to resume treatment within one month. Overall, anew asymptomatic infection was identified in 2 cycles (0.8%), while 4 of the 6 positive SARS-CoV-2 tests were among patients with aprior history of Covid-19. 3 of 4 also had adocumented prior positive RNA test. Our data suggest that universal SARS-CoV-2 screening among fertility patients is feasible, with an approximately 2% positive rate per cycle among the patients of this study. Most positive patients had aprior remote infection, but their infectiousness while being screened remains unclear.Abbreviations: REI: reproductive endocrinology and infertility; IUI: intrauterine insemination; IVF: in vitro fertilization; sono: sonography; cryo: cryopreservation; FET: frozen embryo transfer.

Low-Dose Urinary Human Chorionic Gonadotropin Is Effective for Oocyte Maturation in In Vitro Fertilization/ Intracytoplasmic Sperm Injection Cycles Independent of Body Mass Index.

BACKGROUND: Currently, there is no agreement on the optimal urinary derived human chorionic gonadotropin (u-hCG) dose requirement for initiating final oocyte maturation prior to oocyte collection in in vitro fertilization (IVF), but doses that range from 2500- 15000 IU have been used. We intended to determine whether low dose u-hCG was effective for oocyte maturation in IVF/intracytoplasmic sperm injection (ICSI) cycles independent of body mass index (BMI). MATERIALS AND METHODS: We retrospectively evaluated a cohort of 295 women who underwent their first IVF/ICSI cycles between January 2003 and December 2010 at the Division of Reproductive Endocrinology and Infertility, Wayne State University, Detroit, MI, USA. Treatment cycles were divided into 3 groups based on BMI (kg/ m2): <25 (n=136), 25- <30 (n=84), and ≥30 (n=75) women. Patients received 5000, 10000 or 15000 IU u-hCG for final maturation prior to oocyte collection. The primary outcome was clinical pregnancy rates (CPRs) and secondary outcome was live birth rates (LBRs). RESULTS: Only maternal age negatively impacted (P<0.001) CPR [odds ratio (OR=0.85, confidence interval (CI: 0.79-0.91)] and LBR (OR=0.84, CI: 0.78-0.90). CONCLUSION: Administration of lower dose u-hCG was effective for oocyte maturation in IVF and did not affect the CPRs and LBRs irrespective of BMI. Women's BMI need not be taken into consideration in choosing the appropriate dose of u-hCG for final oocyte maturation prior to oocyte collection in IVF. Only maternal age at the time of IVF negatively influenced CPRs and LBRs in this study.

Trophoblast Retrieval and Isolation From the Cervix for Noninvasive, First Trimester, Fetal Gender Determination in a Carrier of Congenital Adrenal Hyperplasia.

Congenital adrenal hyperplasia (CAH) is an autosomal recessive defect in cortisol biosynthesis that elevates fetal androgen levels to cause genital ambiguity and external genital masculinization in newborn females. Introducing dexamethasone in utero by 7 weeks gestation precludes virilization of affected females. However, identification of a male fetus prior to week 7 could avert the necessity of steroid treatment in half of pregnancies at risk of CAH. We recently introduced trophoblast retrieval and isolation from the cervix (TRIC), an approach that noninvasively isolate homogeneous trophoblast cells from pregnant women as early as 5 weeks gestation, using a Papanicolaou test. Here, we have used TRIC to correctly identify male fetal DNA when both parents were carriers of the mutation that produces CAH and previously produced an affected child. Trophoblast cells (1400) obtained by TRIC were assessed using immunocytochemistry with an antibody against the trophoblast-specific ß subunit of human chorionic gonadotropin, which labeled 100% (17 of 17) of isolated cells, while none of the excluded maternal cervical cells were labeled. The isolated cells were examined by fluorescent in situ hybridization for chromosomes 18, X, and Y at a clinical cytogenetics laboratory, demonstrating 100% (18 of 18) of cells to be diploid 18/XY. Aliquots of DNA obtained from the isolated cells assayed for SRY and RNASEH genes by TaqMan assays confirmed a male fetus. This case study demonstrates the utility of TRIC to accurately identify fetal gender as a means of reducing the need for prophylactic administration of exogenous steroids in pregnancies at risk of CAH.

Rare Müllerian Anomaly: Complete Septate Uterus with Simultaneous Longitudinal and Transverse Vaginal Septa.

BACKGROUND: We present a patient with primary amenorrhea and a rare combination of anomalies. She was found to have a septate uterus, double cervix, and a longitudinal and a low transverse vaginal septum. CASE: An 18-year-old girl with primary amenorrhea presented with severe monthly pelvic pain. Examination and imaging revealed a thin transverse vaginal septum, complete septate uterus, double cervix, and a longitudinal vaginal septum. The transverse and longitudinal vaginal septa were excised and repaired. SUMMARY AND CONCLUSION: Although repetitive pregnancy loss and preterm birth are associated with various Müllerian duct anomalies, clinicians should also be suspicious of the presented anomaly in cases of primary amenorrhea and cyclic pelvic pain. To our knowledge, this is the only case of simultaneous septate uterus with longitudinal and transverse vaginal septum and the second case of combined longitudinal and transverse septum, which caused primary amenorrhea. This rare anomaly further supports the bidirectional regression theory of Müllerian development.

Sildenafil stimulates human trophoblast invasion through nitric oxide and guanosine 3',5'-cyclic monophosphate signaling.

OBJECTIVE: To determine the effect of sildenafil, a phosphodiesterase type 5 inhibitor, on trophoblast invasiveness. DESIGN: Laboratory investigation. SETTING: Academic medical center. PATIENT(S): Placental tissues discarded after first-trimester terminations were obtained from patients with informed consent. INTERVENTION(S): A cell line, HTR-8/SVneo, established from first-trimester cytotrophoblast, and villous explants, was treated with or without sildenafil, guanosine 3',5'-cyclic monophosphate (cGMP) analog, cGMP inhibitor, or L-NAME (N(G)-nitro-L-arginine methyl ester hydrochloride) and cultured on fibronectin or Matrigel. Integrins α6ß4 and α1ß1 were detected by immunocytochemistry. MAIN OUTCOME MEASURE(S): Trophoblast outgrowth from villous tips, cytotrophoblast cell invasion, and integrin immunostaining were assessed in cytotrophoblast and explant cultures. RESULT(S): Integrin expression in trophoblast cells ex vivo switched from α6 to α1, and invasiveness increased, when exposed to sildenafil or cGMP agonist. Either cGMP antagonist or L-NAME blocked integrin switching and invasion induced by sildenafil. Elevation of nitric oxide pharmacologically induced invasion, but not when cGMP antagonist was present. CONCLUSION(S): Sildenafil altered trophoblast phenotype through a process dependent on nitric oxide availability and cGMP accumulation. In addition to its vasoactivity, sildenafil directly stimulates trophoblast extravillous differentiation, which would be favorable for implantation and reduce risk for adverse pregnancy outcomes.

Sildenafil Prevents Apoptosis of Human First-Trimester Trophoblast Cells Exposed to Oxidative Stress: Possible Role for Nitric Oxide Activation of 3',5'-cyclic Guanosine Monophosphate Signaling.

Human first-trimester trophoblast cells proliferate at low O2, but survival is compromised by oxidative stress, leading to uteroplacental insufficiency. The vasoactive drug, sildenafil citrate (Viagra, Sigma, St Louis, Missouri), has proven useful in reducing adverse pregnancy outcomes. An important biological function of this pharmaceutical is its action as an inhibitor of cyclic guanosine monophosphate (cGMP) phosphodiesterase type 5 activity, which suggests that it could have beneficial effects on trophoblast survival. To investigate whether sildenafil can prevent trophoblast cell death, human first-trimester villous explants and the HTR-8/SVneo cytotrophoblast cell line were exposed to hypoxia and reoxygenation (H/R) to generate oxidative stress, which induces apoptosis. Apoptosis was optimally inhibited during H/R by 350 ng/mL sildenafil. Sildenafil-mediated survival was reversed by l-N(G)-nitro-l-arginine methyl ester hydrochloride or cGMP antagonist, indicating a dependence on both nitric oxide (NO) and cGMP. Indeed, either a cGMP agonist or an NO generator was cytoprotective independent of sildenafil. These findings suggest a novel intervention route for patients with recurrent pregnancy loss or obstetrical placental disorders.

Use of gonadotropins for initiation of singleton gestations in non-assisted reproductive technology cycles.

Gonadotropins are a valuable part of the armamentarium available to assist couples in achieving a live birth. Multiple approaches can be used to limit the risk of multiple gestations, but with potential negative impact on establishing pregnancies. Financial considerations often limit enthusiasm for approaches which could reduce success in achieving pregnancy.

Adverse obstetric outcomes associated with sonographically identified large uterine fibroids.

STUDY OBJECTIVE: To determine the impact of sonographically identified large uterine fibroids (>5 cm in diameter) on obstetric outcomes. DESIGN: Retrospective cohort study. SETTING: University teaching hospital. PATIENT(S): Women with singleton gestations (n = 95) noted to have uterine fibroids on obstetric ultrasonography from September 2009 through April 2010 and age-matched controls (n = 95). INTERVENTION(S): None. MAIN OUTCOME MEASURE(S): Obstetric outcomes including short cervix, preterm premature rupture of membranes, and preterm delivery. RESULT(S): Compared to women with no fibroids or small fibroids (≤5 cm), women with large fibroids (>5 cm) delivered at a significantly earlier gestational age (38.6 vs. 38.4 vs. 36.5 weeks). Short cervix, preterm premature rupture of membranes, and preterm delivery were also significantly more frequent in the large fibroid group, and were associated with number of fibroids >5 cm in diameter. Blood loss at delivery was significantly higher in the large fibroid group (486.8 vs. 535.6 vs. 645.1 mL), as was need for postpartum blood transfusion (1.1 vs. 0.0 vs. 12.2%). CONCLUSION(S): Women with large uterine fibroids in pregnancy are at significantly increased risk for delivery at an earlier gestational age compared to women with small or no fibroids, as well as obstetric complications including excess blood loss and increased frequency of postpartum blood transfusion.

Comparison of development and implantation of human embryos biopsied with two different methods: aspiration and displacement.

OBJECTIVE: To compare the development and implantation of human embryos biopsied with two different methods for preimplantation genetic diagnosis (PGD). DESIGN: Technique and method. SETTING: A regional hospital IVF laboratory and private reproductive medicine clinic. PATIENT(S): Women undergoing IVF and PGD. INTERVENTION(S): Day 3 embryos were biopsied with aspiration and displacement; the embryos were cultured to blastocyst stage and then transferred. MAIN OUTCOME MEASURE(S): Blastocyst rate, pregnancy rate, and implantation rate. RESULT(S): One hundred fifty-one embryos from 14 patients were biopsied with the blastomere displacement method and 51 embryos from 5 patients were biopsied with the aspiration method. Displacement used less time than aspiration; thus, the time of embryos exposed to biopsy solution was shorter when displacement was used. Blastocyst formation (55.6%-56.8%) and ongoing pregnancy rate (50%) were not different between the two biopsy methods. However, the implantation rate was significantly higher in patients with embryos biopsied using the displacement method (64.7%) than with the aspiration method (25%). CONCLUSION(S): Blastomere displacement uses less time and is an easy and simple method for embryo biopsy and could be used as an alternative method for embryo biopsy. Our results indicate that the displacement method minimizes embryo damage during biopsy that was indicated by a higher implantation rate.