This study examined prevalence of persistent hypertension following delivery complicated by hypertensive disorders and related obstetric and laboratory risk factors. This prospective cohort study was conducted in a teaching medical center on 270 women with more than 20 weeks of gestation who were admitted for examination and management of high blood pressure. The patients were followed up for blood pressure in two visits at 6 and 12 weeks postpartum. After 12 weeks, women were assigned to three groups of healthy, prehypertension and persistent hypertension. Background information was reviewed to find independent factors associated with persistency of blood pressure using statistical t-test and logistic regression. In bivariate analysis, relative risk of persistent hypertension was estimated at 95% confidence interval. Of 270 patients (46.2%), 110 patients developed persistent hypertension. Among risk factors, high BMI, delivery in less than 34 weeks of pregnancy, history of preeclampsia, history of diabetes, severe preeclampsia and drug control for PIH were independently associated with persistent hypertension. Abnormal laboratory findings included thrombocytopenia, increased serum uric acid and serum creatinine and severe proteinuria associated with this disorder (P <0.05). Almost one in every two pregnant women with hypertensive disorders was prone to postpartum persistent hypertension. This risk particularly increased in maternal obesity, preterm birth due to preeclampsia and abnormal laboratory findings indicating severe preeclampsia. Therefore, more detailed follow-up of high-risk patients is recommended in puerperal visits for diagnosis and timely treatment
