The Lancet: Weight gain increases stillbirth rate Maternal weight gain before having a second child is associated with an increased risk of stillbirth and infant death in the first year of life. This conclusion was reached in a cohort study by Prof. Cnattingius et al at Karolinska Institutet in Sweden and was recently published in THE LANCET, a Medscape interview. Fifteen percent of women had a body mass index (BMI) increase between births of between 2 and 4 (weight gain of 6 to 11 kg), and 6% had a BMI increase of greater than 4. Without accounting for weight gain in the first pregnancy, such weight gain resulted in a 30% to 50% increased risk of stillbirth. For normal-weight women, the same weight gain leads to a 27% to 60% increased risk of first-trimester infant mortality. In contrast, for overweight women, it was found that a reduction in BMI of 2 (6 kg) was associated with a 50% reduction in the risk of death during infancy. Overweight and obesity are becoming a worldwide problem because of the association with pregnancy complications and may be predictive of neonatal mortality. Maternal weight gain between pregnancies is associated with preeclampsia, gestational diabetes, preterm labor and stillbirth. This correlation is more pronounced in normal weight women than in overweight or obese women. Maternal weight gain between births also increases the risk of infant mortality, especially in the neonatal period, but there are no data on whether pre-pregnancy weight gain increases the risk of infant mortality. Professors Cnattingius and Villamor therefore investigated the effect of weight gain between births on stillbirths and neonatal mortality in the second trimester. The researchers conducted a cohort study of birth registry data from Swedish medical centers between 1992 and 2012, which included 456,711 women who gave birth to their first and second child during this period, and assessed the effect of increased BMI in mothers of first- and second-born children on stillbirths (at 28 weeks and beyond) and infant deaths (up to 1 year). Of these participants, 13.1% had a decrease in BMI of ≤1 between births, 45.9% had no change in weight (BMI change of -1 to <1), and 41.1% had an increase in BMI of ≥1. The risk of stillbirth and neonatal death was 1.55 times higher for women with an increase in BMI of >4 compared with women with no significant change in weight between births. The risk of stillbirth increased linearly with increasing BMI, with women with a BMI increase of >4 having a 50% increased risk of stillbirth compared with women with unchanged weight. Normal weight (<25 kg/O) in the first birth and weight gain between births increases infant mortality in the second birth, with BMI increases of 2 to 4 or 4 having a high infant mortality rate. Although weight gain leads to a linear increase in infant mortality, it is only at a BMI increase of ≥4 that mortality increases in young children after 1 year of age. It is worth noting that for women who were overweight with their first child, weight gain between births had no effect on infant mortality. In addition, in overweight women (BMI >25 kg/O), a reduction in maternal BMI by more than 2 significantly reduced infant mortality, but for normal-weight women, losing the same amount of weight increased the risk of infant mortality. In these cohort studies, there was sufficient evidence of an association between weight gain between two births and stillbirths in both normal-weight and overweight women. The studies also found that weight gain between two births also increased the risk of stillbirths that followed. The study suggests that normal weight women should control their weight gain before pregnancy and overweight women should lose weight.