Epidemiology and Mechanisms of De Novo and Persistent Hypertension in the Postpartum Period.

BACKGROUND The pathophysiology of hypertension in the immediate postpartum period is unclear. METHODS AND RESULTS We studied 988 consecutive women admitted to a tertiary medical center for cesarean section of a singleton pregnancy. The angiogenic factors soluble fms-like tyrosine kinase 1 and placental growth factor, both biomarkers associated with preeclampsia, were measured on antepartum blood samples. We then performed multivariable analyses to determine factors associated with the risk of developing postpartum hypertension. Of the 988 women, 184 women (18.6%) developed postpartum hypertension. Of the 184 women, 77 developed de novo hypertension in the postpartum period, and the remainder had a hypertensive disorder of pregnancy in the antepartum period. A higher body mass index and history of diabetes mellitus were associated with the development of postpartum hypertension. The antepartum ratio of soluble fms-like tyrosine kinase 1 to placental growth factor positively correlated with blood pressures in the postpartum period (highest postpartum systolic blood pressure [r=0.29, P<0.001] and diastolic blood pressure [r=0.28, P<0.001]). Moreover, the highest tertile of the antepartum ratio of soluble fms-like tyrosine kinase 1 to placental growth factor was independently associated with postpartum hypertension (de novo hypertensive group: odds ratio, 2.25; 95% confidence interval, 1.19-4.25; P=0.01; in the persistent hypertensive group: odds ratio, 2.61; 95% confidence interval, 1.12-6.05; P=0.02) in multivariable analysis. Women developing postpartum hypertension had longer hospitalizations than those who remained normotensive (6.5±3.5 versus 5.7±3.4 days; P<0.001). CONCLUSIONS Hypertension in the postpartum period is relatively common and is associated with prolonged hospitalization. Women with postpartum hypertension have clinical risk factors and an antepartum plasma angiogenic profile similar to those found in women with preeclampsia. These data suggest that women with postpartum hypertension may represent a group of women with subclinical or unresolved preeclampsia.