Association of Maternal Body Mass Index With Risk of Infant Mortality: A Dose-Response Meta-Analysis.

This study presumed that a high or low body mass index (BMI) might increase the risk of infant mortality. Therefore, a meta-analysis was performed to systematically assess the association between maternal BMI and the risk of infant mortality. The electronic databases, including Pubmed, Embase database, and Cochrane Library, were systemically searched by two investigators from inception to November 26th, 2020, with no language restriction. In parallel, a dose-response was assessed. Finally, 22 cohort studies involving 13,532,293 participants were included into this paper, which showed that compared with normal BMI, maternal overweight significantly increased the risks of infant mortality [risk ratio (RR), 1.16; 95% confidence interval (CI), 1.13-1.19], neonatal mortality (RR, 1.23; 95% CI, 1.08-1.39), early neonatal mortality (RR, 1.55; 95% CI, 1.26-1.92) and post-neonatal mortality (RR, 1.18; 95% CI, 1.07-1.29). Similarly, maternal obesity significantly increased the risk of infant mortality (RR, 1.55; 95% CI, 1.41-1.70), neonatal mortality (RR, 1.55; 95% CI, 1.28-1.67), early neonatal mortality (RR, 1.37; 95% CI, 1.13-1.67), and post-neonatal mortality (RR, 1.30; 95% CI, 1.03-1.65), whereas maternal underweight potentially decreased the risk of infant mortality (RR, 0.93; 95% CI, 0.88-0.98). In the dose-response analysis, the risk of infant mortality significantly increased when the maternal BMI was >25 kg/m. Maternal overweight or obesity significantly increases the risks of infant mortality, neonatal mortality, early neonatal mortality, and post-neonatal mortality compared with normal BMI in a dose-dependent manner. Besides, maternal underweight will not increase the risk of infant mortality, neonatal mortality, early neonatal mortality, or postneonatal mortality; instead, it tends to decrease the risk of infant mortality. Early weight management may provide potential benefits to infants, and more large-scale prospective studies are needed to verify this finding in the future.