Pregnancy outcomes after frozen-thawed single euploid blastocyst transfer following IVF cycles using GNRH agonist or HCG trigger for final oocyte maturation

Effect of GnRH agonist trigger with or without low-dose hCG on reproductive outcomes for PCOS women with freeze-all strategy: a propensity score matching study

PURPOSE

This study aimed to compare the effect of gonadotropin-releasing hormone agonist (GnRHa) trigger alone versus dual trigger comprising GnRHa and low-dose human chorionic gonadotropin (hCG) on reproductive outcomes in patients with polycystic ovary syndrome (PCOS) who received the freeze-all strategy.

METHODS

A total of 615 cycles were included in this retrospective cohort study. Propensity score matching (PSM) was performed to control potential confounding factors between GnRHa-trigger group (0.2 mg GnRHa) and dual-trigger group (0.2 mg GnRHa plus 1000/2000 IU hCG) in a 1:1 ratio. Multivariate logistic regression was applied to estimate the association between trigger methods and reproductive outcomes.

RESULTS

After PSM, patients with dual trigger (n = 176) had more oocytes retrieved, mature oocytes, and 2PN embryos compared to that with GnRHa trigger alone. However, the oocytes maturation rate, normal fertilization rate, and frozen embryos between the two groups were not statistically different. The incidence of ovarian hyperstimulation syndrome (OHSS) (14.8% vs. 2.8%, P < 0.001) and moderate/severe OHSS (11.4% vs. 1.7%, P < 0.001) were significantly higher in dual-trigger group than in GnRHa-alone group. Logistic regression analysis showed the adjusted odds ratio of dual trigger was 5.971 (95% confidence interval 2.201-16.198, P < 0.001) for OHSS. The pregnancy and single neonatal outcomes were comparable between the two groups (P > 0.05).

CONCLUSION

For PCOS women with freeze-all strategy, GnRHa trigger alone decreased the risk of OHSS without damaging oocyte maturation and achieved satisfactory pregnancy outcomes.

Opening the black box: why do euploid blastocysts fail to implant? A systematic review and meta-analysis

BACKGROUND

A normal chromosomal constitution defined through PGT-A assessing all chromosomes on trophectoderm (TE) biopsies represents the strongest predictor of embryo implantation. Yet, its positive predictive value is not higher than 50-60%. This gap of knowledge on the causes of euploid blastocysts' reproductive failure is known as 'the black box of implantation'.

OBJECTIVE AND RATIONALE

Several embryonic, maternal, paternal, clinical, and IVF laboratory features were scrutinized for their putative association with reproductive success or implantation failure of euploid blastocysts.

SEARCH METHODS

A systematic bibliographical search was conducted without temporal limits up to August 2021. The keywords were '(blastocyst OR day5 embryo OR day6 embryo OR day7 embryo) AND (euploid OR chromosomally normal OR preimplantation genetic testing) AND (implantation OR implantation failure OR miscarriage OR abortion OR live birth OR biochemical pregnancy OR recurrent implantation failure)'. Overall, 1608 items were identified and screened. We included all prospective or retrospective clinical studies and randomized-controlled-trials (RCTs) that assessed any feature associated with live-birth rates (LBR) and/or miscarriage rates (MR) among non-mosaic euploid blastocyst transfer after TE biopsy and PGT-A. In total, 41 reviews and 372 papers were selected, clustered according to a common focus, and thoroughly reviewed. The PRISMA guideline was followed, the PICO model was adopted, and ROBINS-I and ROB 2.0 scoring were used to assess putative bias. Bias across studies regarding the LBR was also assessed using visual inspection of funnel plots and the trim and fill method. Categorical data were combined with a pooled-OR. The random-effect model was used to conduct the meta-analysis. Between-study heterogeneity was addressed using I2. Whenever not suitable for the meta-analysis, the included studies were simply described for their results. The study protocol was registered at http://www.crd.york.ac.uk/PROSPERO/ (registration number CRD42021275329).

OUTCOMES

We included 372 original papers (335 retrospective studies, 30 prospective studies and 7 RCTs) and 41 reviews. However, most of the studies were retrospective, or characterized by small sample sizes, thus prone to bias, which reduces the quality of the evidence to low or very low. Reduced inner cell mass (7 studies, OR: 0.37, 95% CI: 0.27-0.52, I2 = 53%), or TE quality (9 studies, OR: 0.53, 95% CI: 0.43-0.67, I2 = 70%), overall blastocyst quality worse than Gardner's BB-grade (8 studies, OR: 0.40, 95% CI: 0.24-0.67, I2 = 83%), developmental delay (18 studies, OR: 0.56, 95% CI: 0.49-0.63, I2 = 47%), and (by qualitative analysis) some morphodynamic abnormalities pinpointed through time-lapse microscopy (abnormal cleavage patterns, spontaneous blastocyst collapse, longer time of morula formation I, time of blastulation (tB), and duration of blastulation) were all associated with poorer reproductive outcomes. Slightly lower LBR, even in the context of PGT-A, was reported among women ≥38 years (7 studies, OR: 0.87, 95% CI: 0.75-1.00, I2 = 31%), while obesity was associated with both lower LBR (2 studies, OR: 0.66, 95% CI: 0.55-0.79, I2 = 0%) and higher MR (2 studies, OR: 1.8, 95% CI: 1.08-2.99, I2 = 52%). The experience of previous repeated implantation failures (RIF) was also associated with lower LBR (3 studies, OR: 0.72, 95% CI: 0.55-0.93, I2 = 0%). By qualitative analysis, among hormonal assessments, only abnormal progesterone levels prior to transfer were associated with LBR and MR after PGT-A. Among the clinical protocols used, vitrified-warmed embryo transfer was more effective than fresh transfer (2 studies, OR: 1.56, 95% CI: 1.05-2.33, I2 = 23%) after PGT-A. Lastly, multiple vitrification-warming cycles (2 studies, OR: 0.41, 95% CI: 0.22-0.77, I2 = 50%) or (by qualitative analysis) a high number of cells biopsied may slightly reduce the LBR, while simultaneous zona-pellucida opening and TE biopsy allowed better results than the Day 3 hatching-based protocol (3 studies, OR: 1.41, 95% CI: 1.18-1.69, I2 = 0%).

WIDER IMPLICATIONS

Embryo selection aims at shortening the time-to-pregnancy, while minimizing the reproductive risks. Knowing which features are associated with the reproductive competence of euploid blastocysts is therefore critical to define, implement, and validate safer and more efficient clinical workflows. Future research should be directed towards: (i) systematic investigations of the mechanisms involved in reproductive aging beyond de novo chromosomal abnormalities, and how lifestyle and nutrition may accelerate or exacerbate their consequences; (ii) improved evaluation of the uterine and blastocyst-endometrial dialogue, both of which represent black boxes themselves; (iii) standardization/automation of embryo assessment and IVF protocols; (iv) additional invasive or preferably non-invasive tools for embryo selection. Only by filling these gaps we may finally crack the riddle behind 'the black box of implantation'.

The association of obesity with euploidy rates in women undergoing in vitro fertilization with preimplantation genetic testing

PURPOSE

The purpose of this study was to determine the impact of body mass index (BMI) on euploidy rates for in vitro fertilization (IVF) cycles with preimplantation genetic testing (PGT) utilizing primarily next-generation sequencing (NGS).

METHODS

This retrospective cohort study included women aged ≤ 45 years who underwent IVF/PGT between September 2013 and September 2020 at a single university-affiliated fertility center. The primary outcome was euploidy rate. Secondary outcomes included peak serum estradiol (E2), number of oocytes retrieved, oocyte maturation rate, high-quality blastulation rate, clinical loss rate (CLR), clinical pregnancy rate (CPR), and ongoing pregnancy/live birth rate (OPR/LBR).

RESULTS

The study included 1335 IVF cycles that were stratified according to BMI (normal, n = 648; overweight, n = 377; obese, n = 310). The obese group was significantly older with significantly lower baseline FSH, peak E2, high-quality blastulation rate, and number of embryos biopsied than the normal group. Overall euploidy rates were not significantly different between BMI groups (normal 36.4% ± 1.3; overweight 37.3% ± 1.8; obese 32.3% ± 1.8; p = 0.11), which persisted after controlling for covariates (p = 0.82) and after stratification of euploidy rate by age group and by number of oocytes retrieved per age group. There were no significant differences in CLR, CPR, and OPR/LBR across BMI groups.

CONCLUSIONS

Despite a lower high quality blastulation rate with obesity, there is not a significant difference in euploidy rates across BMI groups in women undergoing IVF/PGT.

Gonadotropin-Releasing Hormone Agonist Versus Recombinant Human Chorionic Gonadotropin Triggering in Fertility Preservation Cycles

The purpose of this research is to study the efficacy of GnRH-a versus r-hCG triggering in patients who go through fertility preservation cycles. This retrospective cohort study was performed in a tertiary university-affiliated medical center. It includes 191 patients undergoing fertility preservation cycles between May 2013 and September 2018, in which ovulation was induced by either GnRH-a or r-hCG. Main outcome measures were number and rate of mature oocyte. Among treatment cycles with medical indication, GnRH agonist significantly increases the odds for high mature rate by 3.55 (1.30-9.66), while in treatment cycles with social indication, there is no significant effect of the triggering agent. An advantage for GnRH-a triggering was observed in medically indicated preservation cycles.

Oocyte competence is independent of the ovulation trigger adopted: a large observational study in a setting that entails vitrified-warmed single euploid blastocyst transfer

PURPOSE

To assess whether the GnRH-agonist or urinary-hCG ovulation triggers affect oocyte competence in a setting entailing vitrified-warmed euploid blastocyst transfer.

METHODS

Observational study (April 2013-July 2018) including 2104 patients (1015 and 1089 in the GnRH-a and u-hCG group, respectively) collecting ≥1 cumulus-oocyte-complex (COC) and undergoing ICSI with ejaculated sperm, blastocyst culture, trophectoderm biopsy, comprehensive-chromosome-testing, and vitrified-warmed transfers at a private clinic. The primary outcome measure was the euploid-blastocyst-rate per inseminated oocytes. The secondary outcome measure was the maturation-rate per COCs. Also, the live-birth-rate (LBR) per transfer and the cumulative-live-birth-delivery-rate (CLBdR) among completed cycles were investigated. All data were adjusted for confounders.

RESULTS

The generalized-linear-model adjusted for maternal age highlighted no difference in the mean euploid-blastocyst-rate per inseminated oocytes in either group. The LBR per transfer was similar: 44% (n=403/915) and 46% (n=280/608) in GnRH-a and hCG, respectively. On the other hand, a difference was reported regarding the CLBdR per oocyte retrieval among completed cycles, with 42% (n=374/898) and 25% (n=258/1034) in the GnRh-a and u-hCG groups, respectively. Nevertheless, this variance was due to a lower maternal age and higher number of inseminated oocytes in the GnRH-a group, and not imputable to the ovulation trigger itself (multivariate-OR=1.3, 95%CI: 0.9-1.6, adjusted p-value=0.1).

CONCLUSION

GnRH-a trigger is a valid alternative to u-hCG in freeze-all cycles, not only for patients at high risk for OHSS. Such strategy might increase the safety and flexibility of controlled-ovarian-stimulation with no impact on oocyte competence and IVF efficacy.