Objective: To analyze the pregnant outcome of women with chronic hypertension, and to investigate the high risk factors associated with harmful maternal and perinatal prognosis.

Methods: Of the 14 127 deliveries in Peking University First Hospital from Jan 2001 to Dec 2005, 121 pregnant women with chronic hypertension were identified and divided into two groups: chronic hypertension with and without preeclampsia (group PE, 64 cases; group N-PE, 57 cases). The maternal and perinatal outcomes of the two groups and the high risk factors for adverse maternal and perinatal prognosis were analyzed.

Results: (1) The incidence of pregnancy with chronic hypertension was 0.86% (121/14 127). (2) The incidences of placental abruption, pulmonary edema and retinopathy in groups PE and N-PE were 16% (10/64) vs 2% (1/57), 11% (7/64) vs 0 and 41% (26/64) vs 16% (9/57, P < 0.05). (3) Preterm birth rate and preterm birth rate before 32 weeks in groups PE and N-PE were 55% (35/64) vs 16% (9/57) and 27% (17/64) vs 2% (1/57, P < 0.01). (4) The rate of small for gestational age in groups PE and N-PE was 31% (20/64) vs 7% (4/57, P < 0.01). (5) The perinatal mortality and newborn intensive care unit (NICU) admission rate in groups PE and N-PE were 11% (7/64) vs 0 and 33% (21/64) vs 5% (3/57, P < 0.01). (6) Chronic hypertension history > or = 4 years, no systemic therapy, irregular perinatal care and preeclampsia history were high risk factors of preeclampsia superimposed on chronic hypertension (P < 0.05). Chronic hypertension history > or = 4 years was the only independent risk factor by multiple factors logistic regression analysis (P < 0.05).

Conclusions: Maternal and perinatal morbidity and mortality are higher in chronic hypertension with preeclampsia than without preeclampsia. Hypertension history for at least 4 years is an independent risk factor.