AimTo study the effect of follicle sizes of different proportions on oocyte and embryo quality in young and advanced-age patients, and provide evidence for personalized protocol adjustment.MethodsThis was a retrospective real-world data study including a total of 11,462 patients who had started their first in vitro fertilization cycle with a gonadotropin-releasing hormone antagonist (GnRH-ant) protocol during 2018–2021. We classified patients into groups according to the size of the dominant proportion of follicles on the human chorionic gonadotropin (hCG) trigger day: Large, Medium, Small, and Equal (containing equivalent proportions of all three size categories). The Cochran–Mantel–Haenszel test by different Anti-Mullerian Hormone (AMH) and antral follicle count (AFC) was used to compare factors such as the metaphase II (MII) oocyte rate, normal fertilization rate, and two pronuclei (2PN) cleavage rate between groups. General linear model (GLM) analysis was performed for inter-group comparison of the oocyte and embryo quality.ResultsIn patients aged < 35 years and with AMH ≥ 1.2μg/L, the MII oocyte percentages in the Large and Medium groups were significantly higher than in the Small group (P < 0.001). The germinal vesicle (GV) oocyte and unavailable oocyte percentages in the Large and Medium groups were lower than in the Small group (P < 0.001). Among patients aged ≥ 35 years with AFC < 5 and AMH ≥ 1.2μg/L, the GV oocyte percentage in the Large group was significantly lower than in the Medium group (2.54% vs. 4.46%, P < 0.001). In patients < 35 years, the GLM demonstrated that the Large and Medium groups had positively impacted on the development of MII oocyte and live birth rate(LBR) of first embryo transfer(ET)(β>0, all P value < 0.05);and had less likely to develop into unavailable oocyte, degenerated oocyte, GV oocyte and MI oocyte rates relative to the Small group(β<0, all P value < 0.05). And among patients ≥ 35 years, the Medium group had positively impacted on the development of MII oocyte and 2PN rates relative to the Small group(β>0, all P value < 0.05); and had less likely to develop into MI oocytes relative to the Small group(β<0, all P value < 0.05). The GLM indicated that AMH, along with Gn total dose, start dose, and Gn days, had significant impact on oocyte and embryo quality. For young patients, age was not a significant influencing factor, but for advanced-age patients, age influenced the outcomes.ConclusionOur analysis suggests that for young patients (< 35 years), triggering when there is a high proportion of large or medium follicles results in better quality oocytes, while for older patients (≥ 35 years), it is better to trigger when the proportion of medium follicles is no less than that of small follicles. Further research is required to confirm these findings.

Background There are a limited number of studies comparing intrahepatic cholestasis of pregnancy (ICP) and neonatal outcomes in puerperae who spontaneously conceived (SC) and those who conceived via in vitro fertilization (IVF). We aimed to investigate the incidence of intrahepatic cholestasis of pregnancy (ICP) as well as neonatal outcomes between conception via IVF compared with spontaneous conception and screen the risk factors of ICP in IVF. Methods A retrospective cohort study included 4,467 puerperae who conceived via IVF, and 28,336 puerperae who conceived spontaneously and linked the information from neonates. Cochran–Mantel–Haenszel (CMH) analysis and a general linear model (GLM) were used to control bias. We compared the related serum-derived indicators and neonatal outcomes of ICP patients with IVF and SC. Multivariate logistic regression analysis, a forest plot, and nomogram were used to assess impact factors and risk prediction. Results Logistic analysis adjusted for confounders revealed significant differences in the ICP rate of singleton delivery (4.24% vs. 3.41%, adjusted OR = 1.26 [95% confidence interval (CI) 1.03–1.53], P = 0.025) and in groups with total bile acids(TBA) ≥ 40 and < 100 µmol/L (14.77% vs. 10.39%, aOR = 1.31[95% CI 1.06–1.63], P = 0.023) between IVF and SC. When we divided newborns into singleton and twins delivery, the GLM revealed a higher rate with Apgar score < 7 (13.44% vs. 3.87%; aOR = 3.85 [95% CI: 2.07–7.17], P < 0.001) and fetal distress for IVF in comparison with SC (19.32% vs. 5.55%; OR = 3.48 [95%CI: 2.39–6.95], P < 0.001) in the singleton group. In multivariate logistic regression analysis, body mass index (BMI) (aOR = 1.29, P = 0.031), number of embryo transferred (ET) (single ET vs. double ET: aOR = 2.82, P < 0.001), E2 level on the ET day (aOR = 2.79, P = 0.011), fresh ET which compared with frozen ET (FET) (aOR = 1.45, P = 0.014), embryo stage(cleavage embryo vs. Blastocyst, aOR = 1.75, P = 0.009) and severe ovarian hyperstimulation syndrome (OHSS) which compared with non-OHSS (aOR = 3.73, P = 0.006) were independent predictors of ICP. And these predictive factors in the logistic regression model were integrated into the nomogram (C-index = 0.735 [95% CI, 0.702–0.764]); for each patient, higher total points indicated a higher risk of ICP. Conclusion We observed that the ICP rate of singleton delivery was higher in IVF than in SC. In ICP patients, there were higher rates of neonatal Apgar score < 7 and fetal distress in IVF than SC, and found the predictors of ICP in IVF.

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