LETTERS TO THE EDITOR Maternal hypertension and infant growth

The Jornal de Pediatria published, in its 91st volume, a very interesting article entitled: ‘‘Growth of preterm low birth weight infants until 24 months corrected age: effect of maternal hypertension.’’ The authors tackled a very important issue in the context of infant and maternal health worldwide, mainly considering the impact of the gestational period on the offspring’s health and disease pattern during the life course. However, we would like to highlight some points in order to contribute to this subject. According to the Task Force on Hypertension in Pregnancy, the hypertensive disorders in pregnancy are classified into: preeclampsia/eclampsia; chronic hypertension; preeclampsia superimposed on chronic hypertension; and gestational hypertension. In our unpublished systematic review, we analyzed 45 papers (from 2008 to 2015) on the association between hypertensive disorders in pregnancy and offspring’s mediumand long-term health outcomes. We found that the high heterogeneity of results among the studies was mainly caused by different classifications of maternal hypertension, and by the quality of adjustments performed by the authors. Thus, in this article, some methodological questions were raised. Firstly, the authors defined two study groups according to the exposure or not to gestational hypertension syndrome; however, in their study description, it is not clear if women with chronic hypertension were also included in the hypertensive group. It is important to highlight that each hypertensive disorder has a different and complex clinical presentation, with diverse consequences in the offspring. Therefore, it is important that studies address the hypertensive disorders independently (i.e., chronic hypertension vs. gestational hypertension vs. preeclampsia) in their analysis.