Association of pregnancy complications and characteristics with future risk of elevated blood pressure

Pregnancy characteristics are associated with risk of cardiovascular diseases, but their independent associations with hypertension or blood pressure (BP) levels remain uncertain. We linked the Swedish Medical Birth Register with Västerbotten Intervention Program data (Northern Sweden). Using linear and logistic regression, we related pregnancy factors in any prior pregnancy with BP and hypertension at 40 years of age in 15 896 parous women free of prepregnancy hypertension. Pregnancy factors included parity, age at first delivery, preeclampsia, gestational diabetes mellitus, placental abruption, shortest gestational age small for gestational age baby (<third percentile for birth weight) or stillbirth. We defined hypertension as systolic BP ≥140 mm Hg and diastolic BP ≥90 mm Hg or antihypertensive use. Multivariable models were adjusted for all pregnancy factors and potential lifestyle and sociodemographic confounders. At 40 years of age, 1535 women (9.6%) had hypertension. In multivariable models, lower parity, younger age at first birth, preeclampsia, small for gestational age, and placental abruption were independently associated with higher systolic and diastolic BP levels at 40 years of age. Younger age at first birth, preeclampsia, gestational age <32 versus ≥37 weeks, and small for gestational age were independently associated with hypertension. Our findings raise the possibility that earlier and more frequent BP screening may be desirable in women with these pregnancy characteristics.