Objective: To compare cumulative live birth rate (LBR) between progestin-primed ovarian stimulation (PPOS) and GnRH antagonist protocols of preimplantation genetic testing (PGT) cycles in different populations.Methods: This was a retrospective cohort study. A total of 865 patients were enrolled and separate analyses were performed for three populations: 498 patients with predicted normal ovarian response (NOR), 285 patients with PCOS, and 82 patients with predicted poor ovarian response (POR). The primary outcome was cumulative LBR for one oocyte retrieval cycle. The results of response to ovarian stimulation were also investigated, including numbers of oocytes retrieved, MII oocytes, 2PN, blastocysts, good-quality blastocysts, and usable blastocysts after biopsy, as well as rates of oocyte yield, blastocyst formation, good-quality blastocysts, and moderate or severe OHSS. Univariable and multivariable logistic regression analyses were used to identify potential confounders that may be independently associated with cumulative live birth.Results: In NOR, the cumulative LBR of PPOS protocol was significantly lower than that of GnRH antagonists (28.4% vs. 40.7%; P=0.004). In multivariable analysis, the PPOS protocol was negatively associated with cumulative LBR (adjusted OR=0.556; 95% CI, 0.377-0.822) compared to GnRH antagonists after adjusting for potential confounders. The number and ratio of good-quality blastocysts were significantly reduced in PPOS protocol compared to GnRH antagonists (2.82 ± 2.83 vs. 3.20 ± 2.79; P=0.032 and 63.9% vs. 68.5%; P=0.021), while numbers of oocytes, MII oocytes and 2PN did not show any significant difference between GnRH antagonist and PPOS protocols. PCOS patients had similar outcomes as NOR. The cumulative LBR of PPOS group appeared to be lower than that of GnRH antagonists (37.4% vs. 46.1%; P=0.151), but not significantly. Meanwhile, the proportion of good-quality blastocysts in PPOS protocol was also lower compared to GnRH antagonists (63.5% vs. 68.9%; P=0.014). In patients with POR, the cumulative LBR of PPOS protocol was comparable to that of GnRH antagonists (19.2% vs. 16.7%; P=0.772). There was no statistical difference in the number and rate of good-quality blastocysts between the two protocols in POR, while the proportion of good-quality blastocysts appeared to be higher in PPOS group compared to GnRH antagonists (66.7% vs. 56.3%; P=0.182). In addition, the number of usable blastocysts after biopsy was comparable between the two protocols in three populations.Conclusion: The cumulative LBR of PPOS protocol in PGT cycles is lower than that of GnRH antagonists in NOR. In patients with PCOS, the cumulative LBR of PPOS protocol appears to be lower than that of GnRH antagonists, albeit lacking statistical difference, whereas in patients with diminished ovarian reserve, the two protocols were comparable. Our findings suggest the need for caution when choosing PPOS protocol to achieve live births, especially for normal and high ovarian responders.

Is there an association between serum LH levels prior to progesterone administration and live birth rate (LBR) in artificial frozen-thawed embryo transfer (FET) cycles? : Low serum LH levels on the day before progesterone initiation in artificial frozen-thawed blastocyst transfer cycles of ovulatory women are associated with a lower LBR. In artificial FET cycles, exogenous oestrogen and progesterone are administered sequentially to mimic the serum hormone pattern similar to the natural cycle. In oestrogen-only phase, the supplemental oestrogen causes thickening of the endometrium and is sometimes accompanied by a rise in serum LH. However, whether the endogenous LH level in artificial FET cycles is related to clinical outcomes remains unclear. A retrospective cohort study including 3469 artificial frozen-thawed blastocyst transfer cycles was conducted at a tertiary-care academic medical centre between February 2014 and January 2020. A total of 3469 frozen blastocyst transfer cycles were stratified into four groups based on the quartiles of serum LH level before progesterone initiation: <25th percentile (LH < 8.79 mIU/ml), 25–50th percentile (8.79 ≤ LH ≤ 13.91 mIU/ml), 51–75th percentile (13.91 < LH ≤ 20.75 mIU/ml) and >75th percentile (LH > 20.75 mIU/ml). The serum LH level >75th percentile group was considered as the reference group. Patients with polycystic ovarian syndrome or other ovulatory disorders were excluded from the study. We also excluded cycles with an endometrial thickness <7 mm before progesterone initiation and patients with intrauterine adhesions and uterine abnormalities. In order to avoid the interference of BMI, all patients were divided into two categories based on the overweight threshold: BMI <25 kg/m² and ≥25 kg/m², and the impacts of serum LH levels on LBR were investigated separately. Univariable and multivariable logistic regression analysis were performed to adjust for potential confounders. EmpowerStats software and R-project were used to build smooth curve fitting models. Compared with the reference group, the implantation rate significantly decreased with low LH levels (<25th percentile) on the day before progesterone initiation (odds ratio [OR] = 0.74; 95% CI, 0.64–0.86; P = 0.001). Accounting for major covariates, low LH levels were associated with a relatively lower LBR (adjusted OR = 0.649; 95% CI, 0.531–0.794; P < 0.001), mainly due to a lower implantation rate, lower clinical pregnancy rate and higher pregnancy loss rate. Moreover, in the patients with BMI <25 kg/m², low LH was associated with a lower LBR (P < 0.001); while in the overweight subgroup, LBR and LH were not correlated (P = 0.823). The main limitation of this study is its retrospective design. Owing to the relatively small number in the overweight group, the results of the overweight subgroup should be interpreted with caution. The evidence provided in this study shows the importance of serum LH levels on the day before progesterone initiation in patients undergoing artificial FET cycles. Hypothalamic dysfunction may be one of the important causes of a relatively low LH, which is related to impaired pregnancy outcomes. Serum LH levels may be used as one of the clinical indicators to predict pregnancy outcomes. No funding and no competing interest were involved in this study. NA.

Is it possible to develop a quantitative method for detecting parental DNA contamination in conventional IVF using preimplantation genetic testing for aneuploidy (PGT-A)? In this study, a quantification method was established for the parental contamination test (qPCT), which ensured more reliable results, and then verified its effectiveness for vitrified conventional IVF embryos. A total of 120 surplus vitrified blastocysts from patients who underwent prior routine IVF cycles were available for study. The results of the prospective clinical study of qPCT-PGT-A showed that the maternal contamination rate was 0.83% (1/120) and that the risk of paternal contamination was negligible. The 24 frozen embryo transfer cycles resulted in 16 clinical pregnancies, including 13 live births, one late inevitable miscarriage and two ongoing pregnancies. The risk of PGT in embryos with potential parental contamination is relatively low, and PGT-A is applicable for vitrified conventional IVF embryos.

This study aimed to retrospectively analyse the effect of the baseline luteinising hormone/follicle-stimulating hormone ratio (bLH/FSH) on the live-birth rate per fresh-embryo transfer cycle (LBR/ET) in infertile women with polycystic ovary syndrome (PCOS) who received a fresh-embryo transfer. A total of 424 patients with PCOS who underwent the first cycle of in vitro fertilisation (IVF)/intracytoplasmic sperm injection (ICSI) fresh-embryo transfer at our hospital was enrolled. Univariate and multivariate logistic regression analyses, along with curve fitting and a threshold effect analysis, were performed. Baseline LH/FSH levels were a significant (P < 0.05) independent risk factor affecting live birth. In the first IVF/ICSI antagonist treatment cycles, LBR/ET after fresh-embryo transfer was relatively flat, until bLH/FSH was 1.0; thereafter, it started to decrease by 17% for every 0.1-unit bLH/FSH increase. Considering the decline in LBR/ET, it is recommended that PCOS women with bLH/FSH > 1.0 carefully consider fresh-embryo transfer during their first IVF/ICSI.