Abstract
(1) Background: Current evidence indicates that women with polycystic ovarian syndrome (PCOS) undergoing in vitro fertilization (IVF) have an increased likelihood of adverse pregnancy outcomes. The objective of this systematic review was to clarify the role of a PCOS-related high body mass index (BMI) in these unfavourable pregnancy outcomes. (2) Methods: A comprehensive search of electronic databases was conducted to identify studies investigating the impact of high BMI on pregnancy outcomes in women with PCOS undergoing IVF. RevMan software (v5.4) was used to calculate the odds ratio (OR) and 95% confidence interval (CI). (3) Results: Nineteen eligible studies (n = 7680) were identified, including 16 retrospective cohort studies (n = 6934), two prospective cohort studies (n = 525), and one cross-sectional study (n = 221). Pooled analysis showed significantly higher odds of clinical pregnancy (OR, 1.16 [95% CI, 1.04-1.29]; z = 2.73; p = 0.006; I(2) = 30%) and livebirths (OR, 1.88 [95% CI, 1.56-2.27]; z = 6.54; p < 0.0001; I(2) = 55%) in women with PCOS with a normal versus a high BMI. Meta-analysis showed significantly increased odds of miscarriages in women with PCOS with a high versus a normal BMI (OR, 0.76 [95% CI, 0.60-0.95]; z = 2.42; p = 0.02; I(2) = 53%). Pooled analysis of three studies (n = 993) showed significantly higher ORs of gestational diabetes mellitus (OR 3.96 [95% CI 1.62-9.68]; z = 3.01; p = 0.003; I(2) = 58%) and gestational hypertension (OR 2.16 [95% CI 1.32-3.54]; z = 3.05; p = 0.002; I(2) = 68%) in women with PCOS with a high versus a normal BMI. Meta-analysis of three studies reported significantly greater odds of a caesarean section for women with PCOS with a high versus a normal BMI (OR 0.45 [95% CI 0.29-0.69]; z = 3.66; p = 0.0003; I(2) = 0%). (4) Conclusions: The increased likelihood of adverse pregnancy outcomes observed in women with PCOS undergoing IVF seems to be attributable to a PCOS-related high BMI.