The Effect of Early Excessive Weight Gain on the Development of Hypertension in Pregnancy.

Background Previous studies have shown an association between total excessive gestational weight gain and hypertension in pregnancy. However, this may be a reflection of excessive water retention associated with the pathophysiology of hypertensive disorders of pregnancy. Early excessive weight gain, prior to the third trimester, results in greater maternal fat deposition and inflammation, which has also been associated with the development of hypertension. By focusing on early excessive weight gain, the association between maternal weight gain and the future development of hypertension can be examined. Objective To evaluate the association between early excessive maternal weight gain and the development of hypertension during pregnancy. Study Design This was a secondary analysis of a longitudinal cohort study of 1,441 women without chronic hypertension who were enrolled in a prospective study evaluating maternal angiogenic factors and the prediction of preeclampsia. Initial body mass index (BMI) was calculated by weight and height at the first study visit. Early excessive maternal weight gain was defined as weight gain by 28 weeks that exceeded the Institute of Medicine (IOM) guidelines and was calculated utilizing the maximum amount of weight gain per week recommended by the IOM based on the patient's starting BMI (normal: 0.45 kg; overweight: 0.32 kg; obese: 0.27 kg). Hypertension was defined as a sustained systolic blood pressure of ≥140 mm Hg or a diastolic blood pressure of ≥90 mm Hg. Logistic regression was used to determine the association between early excessive weight gain, initial BMI, and the development of hypertension, including gestational hypertension and preeclampsia, during pregnancy. Results Of 1,441 women, 767 (53.2%) had weight gain that exceeded the IOM guidelines in the first 28 weeks and 154 (10.8%) developed hypertension during pregnancy. Women whose weight gain exceeded the IOM guidelines were more likely to develop hypertension even after adjusting for relevant confounders (12.5 vs. 8.6%; p = 0.02; adjusted odds ratio [OR] = 1.70; 95% confidence interval [CI]: 1.18-2.44; p < 0.01). Obese women had a 2.4-fold increased risk of developing hypertension, even after controlling for excessive weight gain (adjusted OR = 2.44; 95% CI: 1.66-3.59; p < 0.01) Conclusions Early excessive maternal weight gain and initial BMI are independently associated with the diagnosis of a hypertensive disorder of pregnancy. Women should be counseled regarding the benefits of achieving a normal BMI prior to pregnancy and appropriate weight gain during pregnancy, as well as the potential harms of excessive weight gain related to perinatal outcomes.