Background Currently, there is no universal criteria for the trigger time of controlled ovarian hyperstimulation (COH), especially with the emerging depot GnRH agonist protocol. It is challenging to explore an indicator that is representative of target follicle cohort development as an alternative to the conventional approach of determining the trigger time based on a few leading follicles. Methods This was a large-sample retrospective analysis. Between January 2016 and January 2020, 1,925 young normal ovarian responders who underwent their first in vitro fertilisation (IVF)/intracytoplasmic sperm injection (ICSI) cycle using the depot GnRH agonist protocol were included. They were divided into three groups based on the dominant follicular proportion (DFP, defined as the ratio of ≥ 18 mm dominant follicles/ ≥ 14 mm large follicles on the human chorionic gonadotropin (HCG) day; Group A: < 30%; Group B: 30%−60%; and Group C: ≥ 60%). The binary logistic regression and multivariate linear regression were used to assess whether the DFP was associated with clinical pregnancy, the number of frozen blastocysts, the blastocyst formation rate, and the low number of frozen blastocysts. Results The logistic regression analysis showed that compared with Group A, the odds ratio (OR) for clinical pregnancy was 1.345 in Group B (P = 0.023), and there was no statistical difference between Group C and Group A (P = 0.216). The multivariate linear regression analysis showed that DFP was negatively associated with the number of frozen blastocysts (β ± SE: Group B vs. Group A = − 0.319 ± 0.115, P = 0.006; Group C vs. Group A = − 0.432 ± 0.154, P = 0.005) as well as the blastocyst formation rate (β ± SE: Group B vs. Group A = − 0.035 ± 0.016, P = 0.031; Group C vs. Group A = − 0.039 ± 0.021, P = 0.067). Furthermore, the OR for the low number of frozen blastocysts was 1.312 in Group B (P = 0.039) and 1.417 in Group C (P = 0.041) compared to Group A. Conclusions For young normal ovarian responders using the depot GnRH agonist protocol, increasing DFP might reduce the developmental potential of oocytes and reduce the number of available blastocysts, and this might result in a lower cumulative pregnancy rate. However, further confirmation using strict prospective randomised controlled studies is required.

BackgroundThere is a higher risk of preterm delivery (PTD) in singleton live births conceived after in vitro fertilization (IVF)/intracytoplasmic sperm injection (ICSI) compared with spontaneously conceived pregnancies. The objective of our study was to build a predictive nomogram model to suggest the possibility of PTD in singleton pregnancies after IVF/ICSI treatment.Method11513 IVF/ICSI cycles with singleton live births were enrolled retrospectively. These cycles were randomly allocated into a training group (80%) and a validation group (20%). We used the multivariate logistics regression analysis to determine prognostic factors for PTD in the training group. A nomogram based on the above factors was further established for predicting PTD. Receiver operating characteristic curves (ROC), areas under the ROC curves (AUC), concordance index (C-index), and calibration plots were analyzed for assessing the performance of this nomogram in the training and validation group.ResultsThere were fourteen risk factors significantly related to PTD in IVF/ICSI singleton live births, including maternal body mass index (BMI) &gt; 24 kg/m2, smoking, uterine factors, cervical factors, ovulatory factors, double embryo transferred (DET), blastocyst transfer, FET, vanishing twin syndrome (VTS), obstetric complications (placenta previa, placenta abruption, hypertensive of pregnancies, and premature rupture of membrane), and a male fetus. These factors were further incorporated to construct a nomogram prediction model. The AUC, C-index, and calibration curves indicated that this nomogram exhibited fair performance and good calibration.ConclusionsWe found that the occurrence of PTD increased when women with obesity, smoking, uterine factors, cervical factors, ovulatory factors, DET, VTS, and obstetric complications, and a male fetus. Furthermore, a nomogram was constructed based on the above factors and it might have great value for clinic use.

Purpose To explore the effect of different concentrations of peak serum estradiol levels on endometrial receptivity quantitatively. Methods In our reproductive medicine center, two best quality of day 3 (D3) embryos were transferred or frozen according to E 2 and progesterone levels on the day of human chorionic gonadotropin (hCG) administration and the number of oocytes retrieved. The remaining embryos were cultured to blastocyst stage and frozen. The patients were then categorized into three groups. The patients with frozen-thawed D3 embryo transfer in artificial cycles without blastocyst frozen served as group 1, those with fresh D3 embryo transfer without blastocyst frozen as group 2, and those with fresh D3 embryo transfer with blastocyst frozen as group 3. Each group was further stratified into 4 sub-groups according to E 2 levels on the day of hCG administration. Clinical pregnancy rate, implantation rate and abortion rate of frozen-thawed and fresh D3 embryo transfer were compared among the three groups in the same stratified E 2 levels. Results For E 2 <7,000 pg/mL, group 1 and group 2 had similar clinical pregnancy rate and implantation rate. But for E 2 ≥7,000 pg/mL, the clinical pregnancy rate in group 1 was significantly higher than in group 2 (p<0.05). For E 2 <7,000 pg/mL, pregnancy rate and implantation rate in group 1 were significantly lower than those in group 3 (P<0.05). But for E 2 ≥7,000 pg/mL, the pregnancy rate in group 1 was significantly higher than in group 3 (P<0.05). There was no significant difference in the abortion rate between group 1 and group 2, or between group 1 and group 3. Conclusions High serum E 2 concentration does not impair implantation and pregnancy rates unless exceeding a certain limit (e.g. 7,000 pg/mL) on the day of hCG administration. Since peak E 2 level was related to OHSS and adverse pregnancy outcomes, further study is needed to set a threshold peak E 2 level for fresh embryo transfer.