Maternal pre‐pregnancy body mass index, gestational weight gain, and pubertal timing in daughters: A systematic review and meta‐analysis of cohort studies

The timing of daughter's puberty onset is constantly earlier. It is still unclear about the maternal pre-pregnancy body mass index (BMI) and gestational weight gain (GWG) as important prenatal factors that may affect offspring's onset of puberty. Thus, we evaluated the association among maternal pre-pregnancy BMI, GWG, and daughters' early pubertal development based on the existing literature. Literature review was conducted in different databases, including Web of Science, Pubmed, Wiley, ScienceDirect, Web of Science, and Chinese National Knowledge Infrastructure databases up to June 2021. We selected random effects model or fixed effects model for meta-analysis according to the I2 statistics value to obtain the summary measurement. A total of 12 cohort studies were included. Compared to maternal pre-pregnancy normal weight, maternal pre-pregnancy overall overweight/obesity (RR = 1.24; 95% CI 1.17 to 1.32), obesity (RR = 1.35; 95% CI 1.23 to 1.48), and overweight (RR = 1.17; 95% CI 1.09 to 1.26) were significantly associated with the increased risk of earlier timing of pubertal onset in daughters. Daughters born of mothers with pre-pregnancy overall overweight/obesity, obesity, and overweight had earlier pubertal onset compared to those born of mothers with normal weight ([mean difference = -3.03, 95% CI: -3.97 to -2.10], [mean difference = -3.50, 95% CI: -5.38 to -1.62], and [mean difference = -2.89, 95% CI: -4.07 to -1.71], respectively). The effects were also significant in the assessed three milestones (menarche, breast development, and pubic hair development). Maternal excessive GWG increased the risk of early pubertal timing in daughters (RR = 1.19; 95% CI 1.09 to 1.30).