Analysis of risk factors of preeclampsia in pregnant women with chronic hypertension and its impact on pregnancy outcomes

Abstract Objective To investigate the risk factors and maternal and fetal outcomes of preeclampsia after pregnancy in patients with primary chronic hypertension. Methods A total of 500 singleton pregnant women with a history of hypertension who were admitted for delivery at our Hospital from March 2015 to May 2022 were retrospectively collected by random sampling and divided into the non-occurrence group ( n = 200) and the occurrence group ( n = 300) according to whether they were complicated by preeclampsia. Afterward, the general data and the pregnancy-related data of patients were collected for comparison. Results The univariate analysis showed significant differences between the non-occurrence group and the occurrence group in terms of the proportion of preeclampsia history (4.00% VS 24.67%, χ2 = 37.383, P < 0.001), duration of hypertension > 3 years (18.00% VS 31.67%, χ2 = 11.592, P < 0.001), systemic therapy (20.50% VS 10.00%, χ2 = 10.859, P < 0.001), gestational age at admission [37.72 (34.10, 38.71) VS 35.01 (31.91, 37.42) weeks, Z = -9.825, P < 0.001]. Meanwhile, the multivariate analysis showed that a history of preeclampsia (OR = 6.796, 95% CI: 3.575 ∼ 10.134, χ2 = 8.234, P < 0.001), duration of hypertension > 3 years (OR = 3.456, 95% CI: 2.157 ∼ 5.161, χ2 = 9.348, P < 0.001), and a lack of systemic antihypertensive treatment (OR = 8.983, 95% CI: 7.735 ∼ 9.933, χ2 = 9.123, P < 0.001) were risk factors for chronic hypertension complicated by preeclampsia during pregnancy. Conclusion A history of preeclampsia, a longer duration of hypertension, and a lack of systematic antihypertensive treatment are risk factors for chronic hypertension complicated by preeclampsia during pregnancy. The occurrence of preeclampsia in pregnant women with chronic hypertension increases the incidence of maternal HELLP syndrome and fetal distress.