To read the full abstract: PLoS Med, 2019;16:e1002744
These investigators painstakingly collated individual-level data from 37 pregnancy and birth cohort studies from Europe, North America, and Australia, comprising 162,129 mothers and their children, in order to identify the optimal levels gestational weight gain in relation to risk of offspring obesity. They confirm excessive gestational weight gain as an independent risk factor to childhood obesity, but its additional effects are small compared to the impact of maternal overweight or obesity before pregnancy.
Guidance on optimal gestational weight gain is difficult to set with confidence. Many countries follow the US Institute of Medicine (IOM) 2009 guidelines, which were based on a combined consideration of various maternal and infant outcomes. The IOM defined separate thresholds of excessive weight gain depending on mothers pre-pregnancy BMI status. Other countries, such as the UK, set no specific weight gain targets.
The current paper revisits the question of optimal gestational weight gain, specifically in relation to the risk of childhood obesity. Unfortunately for those hoping for a simple answer, there does not appear to be any obvious single threshold. Overall the risk of childhood obesity increased linearly with increasing gestational weight gain (adjusted for pre-pregnancy BMI status) and this association was scarcely changed after adjustment for birth weight. Furthermore, gestational weight gain may not be the most effective target in relation to childhood obesity; within each maternal BMI category, excessive gestational weight gain only slightly increased the risk of childhood overweight/obesity.