Association between gestational weight gain and perinatal outcomes in women with chronic hypertension

Background Gestational weight gain above or below the 2009 National Academy of Medicine guidelines has been associated with adverse maternal and neonatal outcomes. Although it has been well established that excess gestational weight gain is associated with the development of gestational hypertension and preeclampsia, the relationship between gestational weight gain and adverse perinatal outcomes among women with pregestational (chronic) hypertension is less clear. Objective The objective of this study was to examine the relationship between gestational weight gain above and below National Academy of Medicine guidelines and perinatal outcomes in a large, population-based cohort of women with chronic hypertension. Study Design This is a population-based retrospective cohort study of women with chronic hypertension who had term, singleton, vertex births in the United States from 2012 through 2014. Prepregnancy body mass index was calculated using self-reported prepregnancy weight and height. Women were categorized into 4 groups based on gestational weight gain and prepregnancy body mass index: (1) weight gain less than, (2) weight gain within, (3) weight gain 1-19 lb in excess of, and (4) weight gain ≥20 lb in excess of the National Academy of Medicine guidelines. The χ² tests and multivariable logistic regression analysis were used for statistical comparisons. Stratified analyses by body mass index category were additionally performed. Results In this large birth cohort, 101,259 women met criteria for inclusion. Compared to hypertensive women who had gestational weight gain within guidelines, hypertensive women with weight gain ≥20 lb over National Academy of Medicine guidelines were more likely to have eclampsia (adjusted odds ratio, 1.93; 95% confidence interval, 1.54–2.42) and cesarean delivery (adjusted odds ratio, 1.60; 95% confidence interval, 1.50–1.70). Excess weight gain ≥20 lb over National Academy of Medicine guidelines was also associated with increased odds of 5-minute Apgar <7 (adjusted odds ratio, 1.29; 95% confidence interval, 1.13–1.47), neonatal intensive care unit admission (adjusted odds ratio, 1.23; 95% confidence interval, 1.14–1.33), and large-for-gestational-age neonates (adjusted odds ratio, 2.41; 95% confidence interval, 2.27–2.56) as well as decreased odds of small-for-gestational-age status (adjusted odds ratio, 0.52; 95% confidence interval, 0.46–0.58). Weight gain 1-19 lb over guidelines was associated with similar fetal growth outcomes although with a smaller effect size. In contrast, weight gain less than National Academy of Medicine guidelines was not associated with adverse maternal outcomes but was associated with increased odds of small for gestational age (adjusted odds ratio, 1.31; 95% confidence interval, 1.21–1.52) and decreased odds of large-for-gestational-age status (adjusted odds ratio, 0.86; 95% confidence interval, 0.81–0.92). Analysis of maternal and neonatal outcomes stratified by body mass index demonstrated similar findings. Conclusion Women with chronic hypertension who gain less weight than National Academy of Medicine guidelines experience increased odds of small-for-gestational-age neonates, whereas excess weight gain ≥20 lb over National Academy of Medicine guidelines is associated with cesarean delivery, eclampsia, 5-minute Apgar <7, neonatal intensive care unit admission, and large-for-gestational-age neonates.