Yao R, et al. - This population-based cohort study aimed to investigate the association between gestational weight gain and risk of stillbirth. With inadequate weight gain and weight loss in all body mass index (BMI) classes, stillbirth risk increased except the morbidly obese group, where weight showed a protective effect. On the other hand, among obese and morbidly obese women, excessive weight gain was correlated with higher risk of stillbirth but was protective against stillbirth in lower weight women.

• Between 2006 and 2011, the physicians included retrospective cohort study utilizing the Texas vital records database, with 2,230,310 births (5,502 stillbirths) for analysis.
• They categorized pregnancies as adequate weight gain, excessive weight gain, inadequate weight gain or weight loss based on the IOM 2009 recommendations.
• They estimated hazard ratios for stillbirth for each gestational weight gain stratum using adequate weight gain as the comparison group.
• For each BMI class, the analysis was performed separately.

• Except morbidly obese, both inadequate weight gain and weight loss were correlated with an increased risk of stillbirth for all BMI classes.
• The physicians observed highest risk in weight loss groups after 36 completed weeks (normal weight: HR = 18.85, [8.25, 43.09]; overweight: HR = 5.87, [2.99, 11.55]; obese: HR = 3.44 [2.34, 5.05]).
• In morbidly obese women, weight loss was associated with reducing stillbirth risk between 24-28 weeks (HR = 0.56, [0.34, 0.95]).
• Among obese and morbidly obese women, excess weight gain was correlated with an increased risk of stillbirth, with the highest risk after 36 completed weeks (Obese: HR = 2.00, [1.55, 2.58]; Morbidly obese: HR = 3.16, [2.17, 4.62]).
• On the other hand, in normal-weight women, excess weight gain was associated with reduced risk of stillbirth between 24-28 weeks (HR = 0.57, [0.44, 0.70]) and in overweight women between 29-33nweeks (HR = 0.62, [0.45, 0.85]).
• For the underweight group, analysis was limited by sample size.
• In this group, both excessive weight gain and inadequate weight gain were not correlated with stillbirth.