Association between clinical and IVF laboratory parameters and miscarriage after single euploid embryo transfers

Background The goal of this study was to investigate which factors, excluding embryo aneuploidies, are associated with miscarriage in patients who have undergone a single euploid blastocyst transfer. Methods Retrospective, observational and multicenter study with 2832 patients undergoing preimplantational genetic testing for aneuploidies (PGT-A) due to repeated implantation failure, recurrent pregnancy loss, advanced maternal age or severe male factor were transferred one single euploid embryo. Results One of the main findings was a significant relationship between body mass index (BMI) and miscarriage rates (13.4% in underweight women, 12.1% in normal weight, 14.5% in overweight, and 19.2% in obese women, odds ratio [OD] 1.04; 95% confidence interval [CI], 1.01–1.07 p = 0.006). Endometrial thickness (OD 0.65; 95%, 0.52–0.77 p = 0.04) and type of endometrial preparation (natural cycle or hormone replacement cycle) (OD 0.77; 95%, 0.52–0.77, p = 0.04) were also associated with miscarriage rates. Conclusions BMI was strongly associated to miscarriage rates. We also observed a weaker association with endometrial thickness and with the type of endometrial preparation (natural cycle or hormone replacement cycle). None of the other studied variables (biopsy day, maternal and male age, duration of infertility, cycle length, previous miscarriages, previous live births, previous In Vitro Fertilization (IVF) cycles, endometrial pattern and/or diagnosis) were associated with miscarriage rates.

The impact of preimplantation genetic testing for aneuploidy on prenatal screening

Objectives To determine whether preimplantation genetic testing for aneuploidy (PGT-A) is associated with a reduced risk of abnormal conventional prenatal screening results in singleton pregnancies conceived using in vitro fertilization (IVF). Methods This was a retrospective cohort study of singleton IVF pregnancies conceived from a single tertiary care center between January 2014 and September 2019. Exclusion criteria included mosaic embryo transfers, vanishing twin pregnancies, and cycles with missing outcome data. Two cases of prenatally diagnosed aneuploidy that resulted in early voluntary terminations were also excluded. The primary outcome of abnormal first or second-trimester combined screening results was compared between two groups: pregnancy conceived after transfer of a euploid embryo by PGT-A vs. transfer of an untested embryo. Multivariable backwards-stepwise logistic regression with Firth method was used to adjust for potential confounders. Results Of the 419 pregnancies included, 208 (49.6%) were conceived after transfer of a euploid embryo by PGT-A, and 211 (50.4%) were conceived after transfer of an untested embryo. PGT-A was not associated with a lower likelihood of abnormal first-trimester (adjusted OR 1.64, 95% CI 0.82–3.39) or second-trimester screening results (adjusted OR 0.96, 95% CI 0.56–1.64). The incidences of cell-free DNA testing, fetal sonographic abnormalities, genetic counseling, and invasive prenatal diagnostic testing were similar between the two groups. Conclusions Our data suggest that PGT-A is not associated with a change in the likelihood of abnormal prenatal screening results or utilization of invasive prenatal diagnostic testing. Counseling this patient population regarding the importance of prenatal screening and prenatal diagnostic testing, where appropriate, remains essential.

Is day 5 blastocyst better than day 6 blastocyst? Evidence from NGS-based PGT-A results

Background Aneuploidy is the principal genetic factor leading to the failure of embryo implantation. For most patients who accept the non-preimplantation genetic testing (PGT) cycle, non-invasive methods to select euploid embryos with the best pregnancy potential are desirable Methods This retrospective study recruited women undergoing PGT for aneuploidy (PGT-A) with trophectoderm biopsy from January 2019 to December 2020. The ploidy status of embryos was determined by next generation sequencing (NGS). Results Altogether 2531 blastocysts from 839 PGT-A cycles were evaluated. The euploid rate of day 5 blastocysts seemed to be significantly higher than that of day 6 blastocysts, either from the same ovarian stimulation (OS) cycles (49.9% vs 35.7%, P < 0.001) or from different OS cycles (48.2% vs 27.8%, P < 0.001). Both the younger maternal age (adjusted OR = 0.917, 95% CI: 0.892–0.944, P < 0.001) and day 5 stage (adjusted OR = 1.735, 95% CI: 1.415–2.127, P < 0.001) were independently associated with the greater euploid rate of blastocysts. However, after single euploid embryo transfer, the clinical outcomes of day 5 blastocysts were comparable to those of day 6 blastocysts, no matter whether they were from the same OS cycles or not. Conclusions Our results revealed that day 5 blastocysts possess a higher euploid rate than day 6 blastocysts independent of the OS cycles. Giving priority to a day 5 blastocyst over day 6 blastocyst will increase the likelihood to select single euploid embryo for transfer in non-PGT cycles.