The effect of body mass index on neonatal outcomes in Chinese women with polycystic ovary syndrome

AIM: This study aimed to explore the effect of body mass index (BMI) on neonatal outcomes in patients with polycystic ovary syndrome following the frozen embryo transfer (FET). METHODS: This study included 1,676 singletons born from mothers with polycystic ovary syndrome (PCOS) after FET between 1 Jan 2007 and 31 Dec 2019. BMI was categorized into three groups: underweight (BMI less than 18.5 kg/m(2)), normal weight (BMI between 18.5 and 24.9 kg/m(2)), and overweight (BMI between 25.0 and 29.9 kg/m(2)). Logistic regression models with generalized estimating equations were used for clustering by patients to explore the effect of BMI on neonatal outcomes. RESULTS: When compared to normal-weight mothers, the rate of large for gestational age (LGA) babies (adjusted odds ratio [aOR] 0.45, 95% confidence interval [95%CI] 0.22–0.93) significantly decreased for underweight mothers and significantly increased (aOR 1.82, 95%CI 1.38–2.41) for overweight mothers. The rate of high birth weight among infants from overweight mothers (aOR 1.75, 95%CI 1.15–2.65) was significantly higher than those from normal-weight mothers after adjusting for known confounding factors. The rate of small for gestational age (SGA) singleton (aOR 2.37, 95%CI 1.14–4.93) was lower among underweight mothers than normal-weight mothers. CONCLUSION: Maternal underweight was a significant protective factor against LGA infants for singletons born from patients with PCOS after FET, whereas maternal overweight was an adverse factor for LGA infants.