Risks of hypertensive disorders in the second pregnancy

This study examined the incidence of and risk factors for recurrent and new ly developed hypertensive disorders in the second pregnancy. We analysed da ta on 1641 women who had both the first and second pregnancies in the Colla borative Perinatal Project, a large prospective cohort study at 12 hospital s in the US. Nineteen per cent [95% CI 14%, 24%] of women who had gestation al hypertension in the first pregnancy, 32% [95% CI 17%, 48%] of those with pre-eclampsia and 46% [95% CI 32%, 60%] of patients with gestational hyper tension or pre-eclampsia superimposed on chronic hypertension, had recurren t hypertensive disorders in the second pregnancy. Risk factors for recurren ce included history of chronic hypertension and thromboembolism, early onse t of hypertension in the first pregnancy or persistent hypertension after 5 weeks postpartum and high baseline blood pressure in the second pregnancy. Women with a normotensive first pregnancy but a severe small-for-gestation al-age birth had twice the risk of developing hypertension in the second pr egnancy (RR = 2.1, 95% CI, 1.1, 4.0). In summary, hypertensive disorders ha ve a 20-50% recurrence rate in the second pregnancy. The earlier the onset of hypertension in the first pregnancy, the higher the overall recurrence r ate. Intrauterine growth restriction of the first birth is an independent r isk factor for hypertension in the second pregnancy.