Santos S, et al. - Researchers examined how maternal pre-pregnancy body mass index (BMI) and gestational weight gain, separately and in combination, are associated with the risks of pregnancy complications. In addition, they sought for their population impact. They performed individual participant data meta-analysis of 39 cohorts including 265,270 births. Findings revealed risks of pregnancy complications in correlation to maternal pre-pregnancy BMI and gestational weight gain are, across their full ranges. They noted the highest risk of pregnancy complications for obese mothers with high gestational weight gain. They suggest promoting a healthy pre-pregnancy BMI and gestational weight gain in order to lower the burden of pregnancy complications and eventually the risk of maternal and neonatal morbidity.