Association between preconception body mass index and fertility in adult female: A systematic review and meta-analysis

Obesity potentially reduces fertility, but systematic reviews are lacking to summarize the existing literature. Therefore, we systematically summarized the association between preconception body mass index (BMI) and fertility in adult female based on existing reports. Up to September 2023, we conducted literature retrievals in different databases, including Web of Science, PubMed, Wiley, and ScienceDirect. Finally, 18 studies were included. Female with overweight/obesity (FOR = 0.85; 95% CI: 0.80, 0.90), obesity (FOR = 0.76; 95% CI: 0.69, 0.83), and overweight (FOR = 0.93; 95% CI: 0.88, 0.99) was associated with the significant time-to-pregnancy (TTP) prolongation (reduced fecundability). Interestingly, underweight was moderately associated with prolonged TTP in females (FOR = 0.95; 95% CI: 0.91, 0.99). Female overweight/obesity was associated with an increased risk of subfecundity (OR = 1.44; 95% CI: 1.20, 1.72) and infertility (OR = 1.60, 95% CI: 1.31-1.94). The findings emphasize the importance of considering appropriate preconception BMI at the population level for female fertility outcomes. In particular, prepregnancy obesity in females is strongly associated with prolonged TTP and increased risk of subfecundity. Scientific management of preconception BMI may improve fertility.