Are pregnancy-associated hypertensive disorders so sweet?

Abstract

Worldwide, one in seven pregnancies is complicated by some form of diabetes, with a rising trend. Additionally, hypertension is one of the main causes of morbidity and mortality for both the pregnant woman and the fetus and also contributes to premature birth. In a cohort study of pregnant women with diabetes, which was recently published in this journal, at least 84.5% of the subjects had hypertension. This rate of hypertension might be among the highest reported thus far. In the medical literature, approximately 20% of women with diabetes during pregnancy have various pregnancy-associated hypertensive disorders. Racial/ethnic differences, apparently, were not implicated in this elevated rate of hypertension: Although black and Hispanic women have a twofold higher rate of hypertension in pregnancy compared to white women, 75% of the subjects in the study in question were white. Thus, the impressive finding delivered by this large study, merits additional clarifications.

Key Words: Pregnancy; Hypertension; Pre-eclampsia; Diabetes; Gestational diabetes; Human

Core Tip: In a recent large study of pregnant women with diabetes, more than 84.5% of the subjects had hypertension, a rate which is fourfold higher than in the literature. Such a finding merits additional clarification.

TO THE EDITOR

We read with interest the paper by Xaverius et al[1] focusing on the association between different phenotypes of diabetic pregnancies and birth outcomes. In this paper, the authors considered, reasonably, gestational or chronic hypertension to be a confounding factor, because hypertension in pregnancy was related to both the predictor and outcome of their investigation. It is striking that most pregnant women with diabetes included in this study had hypertension (with rates ranging from 84.5% to 95.0%)[1]. To the best of our knowledge, this rate of hypertension might be among the highest reported thus far. A tentative explanation could be that racial/ethnic differences were implicated in this elevated rate of hypertension: black and Hispanic women have a twofold higher rate of hypertension in pregnancy compared to white women[2]. Nevertheless, approximately 75% of the population which was included in the study by Xaverius et al[1] were white. In the Control of Hypertension in Pregnancy Study (CHIPS), which included women with gestational or chronic hypertension[3], only 6% had gestational diabetes at enrollment, while in the recent Chronic Hypertension and Pregnancy (CHAP) trial, which included only women with chronic hypertension[4], the reported gestational diabetes rate was 15%. Additionally, in the literature, approximately 20% of women with diabetes during pregnancy have various pregnancy-associated hypertensive disorders[5-7]. Thus, in the study by Xaverius et al[1] the rate of hypertension in pregnancy is fourfold higher than in the literature. This impressive finding, delivered by this large pregnancy cohort[1], merits additional clarifications.