Gestational weight gain as a risk factor for hypertensive disorders of pregnancy

OBJECTIVE: Pregnancy interventions to limit gestational weight gain (GWG) have been proposed as a means of preventing hypertensive disorders of pregnancy (HDP); however, it is currently unclear whether GWG has a causal influence on the development of HDP. Thus, we aimed to determine whether GWG in early pregnancy is a risk factor for preeclampsia and gestational hypertension and whether GWG precedes the increases in blood pressure in normotensive women across pregnancy. STUDY DESIGN: We examined repeat antenatal clinic measurements of weight and blood pressure (median of 12 and 14 per woman, respectively) of 12,522 women in the Avon Longitudinal Study of Parents and Children. RESULTS: Greater prepregnancy weight was associated with an increased risk of gestational hypertension and preeclampsia per 10 kg of prepregnancy weight: odds ratio (OR), 1.80; 95% confidence interval (CI), 1.70-1.91 and OR, 1.71; 95% CI, 1.49-1.95, respectively, for women weighing 90 kg or less before pregnancy; OR, 1.24; 95% CI, 1.03-1.49 and OR, 1.61; 95% CI, 1.18-2.19 for women weighing more than 90 kg. Fully adjusted odds ratios for gestational hypertension and preeclampsia per 200 g per week GWG up to 18 weeks were OR, 1.26; 95% CI, 1.16-1.38 and OR, 1.31; 95% CI, 1.07-1.62. In normotensive women, GWG in early pregnancy was associated positively with blood pressure change in midpregnancy and negatively with blood pressure change in late pregnancy. In all gestational periods, GWG was positively associated with concurrent blood pressure change. However, there was no evidence that blood pressure changes in any period were associated with subsequent GWG. CONCLUSION: These findings suggest that GWG in early pregnancy may be a potential target for interventions aimed at reducing the risk of HDP.