Background Hypertensive disorders of pregnancy are related to higher offspring blood pressure (BP) but it is not known whether this association strengthens or weakens as BP changes across childhood. of women who had existing hypertension gestational hypertension or preeclampsia during pregnancy had on average higher BP at age 7 years compared to offspring of normotensive pregnancies (mean difference [95%CI] in systolic BP: 1.67 mm Hg [0.48 2.86 1.98 mm Hg [1.32 2.65 and 1.22 mm Hg [?0.52 2.97 respectively). These differences were consistent across childhood to age 18 years as the patterns of BP change did not differ between offspring of hypertensive pregnancies and normotensive pregnancies. Maternal BP at 8 weeks’ gestation was also positively associated with offspring BP in childhood and adolescence but changes in BP across pregnancy were not strongly associated. Conclusions The differences in BP between offspring of hypertensive pregnancies and offspring of normotensive pregnancies remain consistent across childhood and adolescence. These associations appear to be most contributed to by higher maternal BP in early pregnancy rather than by pregnancy-related BP changes. Keywords: ALSPAC blood pressure change childhood gestational hypertension preeclampsia pregnancy Hypertensive disorders of pregnancy (HDP) include pregnancy-induced hypertension (ie gestational hypertension and preeclampsia) and also hypertension that exists prior to pregnancy (referred to as existing hypertension here). Pregnancy-induced hypertension is usually defined as newly elevated blood pressure (BP) after 20 weeks of gestation with preeclampsia being distinguished from gestational hypertension by the presence of proteinuria.1 Preeclampsia is also characterized by systemic inflammation insulin resistance and endothelial dysfunction.2-5 Preeclampsia and gestational hypertension have been shown to be associated with higher BP in offspring during childhood and adolescence.6-15 However it is not clear how this association compares with the association of existing hypertension with offspring BP.16 Despite the different forms VU 0357121 of HDP VU 0357121 having different clinical manifestations there is clear overlap between them and increasing evidence that they may not be entirely distinct conditions with higher BP (even within the normal range) prior to pregnancy predisposing to the Cetrorelix Acetate development of preeclampsia.17 In addition existing hypertension has VU 0357121 recently been shown to be strongly associated with the risk of a similar range of perinatal factors including perinatal mortality preterm delivery and low birth weight to preeclampsia and gestational hypertension.18 19 Comparing BP across offspring of pregnancies affected by existing hypertension gestational hypertension preeclampsia and offspring of normotensive pregnancies may provide information about the mechanisms influencing the associations and whether there are distinct or common pathways involved for each of the forms of HDP.7 BP increases with age during childhood and adolescence 20 with some studies suggesting that BP decreases in females in late adolescence.23-27 Previous studies that examined associations of HDP with offspring BP have all focused on a single measurement occasion and no studies to our knowledge have assessed whether HDP is associated with age-related changes in BP across childhood and adolescence using repeated measurements of BP. This would provide information about the development of cardiovascular VU 0357121 VU 0357121 risk and whether the differences seen in BP during VU 0357121 childhood between offspring of normotensive and hypertensive pregnancies become smaller as the child ages or strengthen into adulthood. An additional way of examining the reported association between maternal HDP and offspring BP is usually to assess the maternal trajectory of BP change during pregnancy. Despite HDP being defined by thresholds of BP pregnancy is a period of considerable BP change and both the BP level in early pregnancy and the rate of increase in BP in late pregnancy is greater in hypertensive pregnancies.28 Hence identifying whether the early-pregnancy BP level or the rate of increase in BP during late pregnancy is usually more strongly related to changes in BP in the offspring may suggest whether the associations between HDP and higher offspring BP.