The effect of obesity on fertility: A systematic review

Obesity and female infertility are two rising public health issues. The relationship between them has been partially explored; however, systematic reviews summarizing the impact of obesity on female infertility are limited.

We investigated the relationships between obesity and infertility outcomes in adult females, through a systematic review using PubMed and Scopus databases.

Findings from 14 studies concluded that obese women (as defined by body mass index - BMI) and centrally obese women (as defined by waist circumference - WC) experienced prolonged time to pregnancy (TTP) and a gradually increased risk of infertility compared to women with normal values for these indicators. Among the three obesity indicators, WC followed by BMI appeared to increase infertility risk when values exceeded normal thresholds. The waist-hip ratio - WHR indicator, though less frequently studied, displayed variability in results regarding TTP. As for linearity, this was investigated only for WC and BMI, revealing non-linear relationships with infertility risk and TTP, respectively. The relationship between obesity and infertility outcome is presented as positive, particularly in the case of central obesity in women of reproductive age. Overweight women experience negative effects on fertility, though not at the extent that appear on obese women.

The present study highlights the need for maintaining a healthy, normal weight for better fertility outcomes. Further research to uncover the deeper mechanisms of obesity that cause reproductive problems in women and their connection with various obesity indicators is encouraged.