Hypertension in pregnancy: A signal of chronic hypertension?

High blood pressure (BP) during pregnancy and in the first 6 weeks postpartum may be an indicator of long-term hypertension, according to results of a prospective, single-centre study presented at SMFM 2021.

“Despite entering prenatal care with similar BPs, we concluded that women with persistent hypertension had a more adverse BP trajectory in the immediate postpartum period compared with women who were normotensive at 6–18 months postpartum,” said study co-lead author Dr Eesha Dave from the University of Pittsburgh Medical Center (UPMC) Magee-Womens Hospital in Pittsburgh, Pennsylvania, US.

Participants were 368 women with hypertensive disorders of pregnancy (HDP) who delivered between February 2018 and June 2019 and who did not have chronic hypertension prior to pregnancy. Only women with BP data 6–18 months postpartum were included. Home BP data was obtained via a remote postpartum hypertension monitoring programme, where women recorded their BP at home for the first 6 weeks postpartum, resulting in 5,958 BP readings.

At a mean 12.9 months postpartum, 49.5 percent of women (n=182) had persistent hypertension, defined as systolic BP ≥130 mmHg, diastolic BP ≥80 mmHg, or use of any anti-hypertensive medication. [SMFM 2021, abstract 53]

Women who had hypertension at follow-up had higher pre-pregnancy body mass index (BMI) than those without hypertension (28.8 vs 25.4 kg/m²; p<0.01), and there was a greater proportion of women who were obese (BMI ≥30 kg/m²) in the hypertensive vs normotensive group (44.0 percent vs 26.6 percent). BP at initial prenatal visit did not differ between those who were hypertensive and normotensive at follow-up (SBP/DBP: 117/73 and 116/72 mmHg, respectively).

Race, maternal age, gestational age at delivery, birthweight, and type of HDP (preeclampsia or gestational hypertension) did not differ between groups. A similar number of women in both groups were prescribed antihypertensive medications at discharge (n=43 vs 41).

A comparable proportion of women who were hypertensive and normotensive attended follow-up (84.6 percent vs 90.9 percent; p=0.07), and a similar number were on antihypertensive medications (20.1 percent vs 16.6 percent; p=0.4). However, BP was higher among women who developed hypertension compared with normotensive women (SBP/DBP: 124/81 vs 117/75 mmHg; p<0.01), and remained so at long-term follow-up (129/84 vs 114/71 mm Hg; p<0.01), with 9.9 percent of women with hypertension on antihypertensive medications.

Women with persistent hypertension had a slower decline in both systolic and diastolic BP within the first 6 weeks postpartum than those without hypertension. Women with persistent hypertension also had higher mean BP readings at the end of the postpartum monitoring programme than normotensive women, with results consistent after adjusting for pre-pregnancy BMI, HDP type, and overweight/obesity.

“HDPs have been identified by [the American College of Cardiology and American Heart Association] as an independent risk factor for future cardiovascular disease including heart failure, stroke, myocardial infarction, and chronic hypertension,” said Dave.

Unfortunately, risk stratifying this population has proved a challenge as many women are lost to follow-up following the postpartum period, she said.

“By leveraging data from our widely scaled postpartum hypertension remote monitoring programme, we were able to discover that a woman’s BP in the first 6 weeks after childbirth appears to be an important indicator of whether she is likely to develop chronic hypertension 6–18 months later,” said Dave.

“This information helps us to better identify women who may be at risk of developing cardiovascular problems later in life and take preventative steps,” added co-lead author Assistant Professor Alisse Hauspurg, also from UPMC Magee-Womens Hospital.