Adverse pregnancy outcomes common in women with chronic hypertension

According to a recent study in the British Medical Journal, women who suffer from chronic hypertension are at higher risk of adverse pregnancy outcomes like low birth weight and neonatal death.

Researchers from King’s College London performed a systematic review using Embase, Medline, and Web of Science to find studies involving pregnant women with chronic hypertension, which included retrospective and prospective cohorts, population studies, and appropriate arms of randomized controlled trials. Fifty-five eligible studies were found, involving 795,221 pregnancies.

Women who had chronic hypertension had high pooled incidences of superimposed preeclampsia (25.9%, 95% confidence interval [CI] 21.0% to 31.5 %), caesarean section (41.4%, 95% CI 35.5% to 47.7%), preterm delivery <37 weeks’ gestation (28.1%, 95% CI 22.6% to 34.4%), birth weight <2500 g (16.9%, 95% CI 13.1% to 21.5%), neonatal unit admission (20.5%, 95% CI 15.7% to 26.4%), and perinatal death (4.0%, 95% CI 2.9% to 5.4%). When compared with women from the US national population dataset, women with chronic hypertension were shown to have higher risks of adverse outcomes: relative risks were 7.7 (95% CI 5.7 to 10.1) for superimposed preeclampsia compared with preeclampsia, 1.3 (95% CI 1.1 to 1.5) for cesarean section, 2.7 (95% CI 1.9 to 3.6) for preterm delivery <37 weeks’ gestation, 2.7 (95% CI 1.9 to 3.8) for birth weight <2500 g, 3.2 (95% CI 2.2 to 4.4) for neonatal unit admission, and 4.2 (95% CI 2.7 to 6.5) for perinatal death.

The investigators concluded that adverse outcomes in pregnancy can be common in women who suffer from chronic hypertension. They felt that the results highlight the need for heightened antenatal surveillance and believe that their study’s findings should be used to inform counseling and pre-pregnancy management in women with chronic hypertension. 

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