Associations of menstrual cycle length with GDM and gestational hypertension in frozen embryo transfer.

BACKGROUND: Prolonged menstrual cycles may indicate potential cardiometabolic conditions; however, there are limited data on how these associations vary among women without polycystic ovary syndrome (PCOS) undergoing in vitro fertilization (IVF). In this study, we aimed to investigate the association between menstrual cycle length, pregnancy complications, and adverse birth outcomes among women without PCOS undergoing frozen embryo transfer (FET). METHODS: Women who delivered singleton live births and had complete pre-pregnancy menstrual cycle data were eligible for inclusion in this study, and were grouped according to the menstrual cycle length (≤ 27, 28-31, 32-35, and ≥ 36 days). Multivariable logistic regression models adjusted for age, body mass index, parity, infertility factors, IVF-FET parameters, and embryo characteristics were used to estimate the adjusted odds ratios (aORs) for gestational diabetes mellitus (GDM) and gestational hypertension. RESULTS: Women with prolonged cycles (≥ 36 days) had a higher risk of GDM (aOR 1.54; 95% confidence interval [CI]: 1.14-2.09; P = 0.005) and gestational hypertension (aOR 1.60; 95% CI: 1.05-2.42; P = 0.027) compared with those with 28-31 day cycles. Cycle lengths of 32-35 days were also associated with an increased risk of gestational hypertension (aOR 1.59; 95% CI: 1.02-2.48; P = 0.041). Short cycles (≤ 27 days) were linked to a reduced risk of GDM (aOR 0.48; 95% CI: 0.30-0.76; P = 0.002). CONCLUSIONS: A prolonged menstrual cycle is a significant risk factor for GDM and gestational hypertension in women undergoing FET. These findings underscore the need for individualized risk assessment and early intervention in IVF patients with prolonged cycles.