Self-monitoring improves postpartum BP control in women with hypertensive pregnancy

Empowering mums to self-monitor their blood pressure (BP) with a physician-guided titration of antihypertensive medications helps lower postpartum BP level after a pregnancy complicated by hypertension, as shown in the POP-HT trial.

In the primary analysis, the 24-hour mean diastolic BP at 9 months postpartum was significantly lower in the intervention group than in the control group (71.2 vs 76.6 mm Hg; difference, −5.80 mm Hg, 95 percent confidence interval [CI], −7.40 to −4.20; p<0.001). [Kitt J, et al, AHA 2023]

Moreover, the intervention group had 6.5-mm Hg lower 24-hour mean systolic BP (114.0 vs 120.3 mm Hg; difference, −6.51 mm Hg, 95 percent CI, −8.80 to −4.22; p<0.001).

Women in the intervention group had to self-measure their BP once daily or twice daily if BP levels were beyond the normal range. A wireless, Bluetooth-enabled upper arm BP cuff was used, with the BP measurements uploaded via a smartphone app. This app provided notifications to either continue current dosing or to titrate the medication dose under the guidance of a physician.

On the other hand, women in the control group received standard of care, which consisted of BP review at 7 to 10 days postpartum and a doctor visit at 6 to 8 weeks. All women had four follow-up postpartum visits.

“POP-HT demonstrates a >5-mm Hg diastolic and almost 7-mm Hg systolic BP improvement,” reported lead study author Dr Jamie Kitt from the University of Oxford in Oxford, England.

Kitt pointed out that if maintained longer term, a 5-mm Hg improvement in BP would cut one’s lifetime cardiovascular risk by about 20 percent.

Fewer readmissions

The self-monitoring intervention was also associated with fewer postnatal readmissions for elevated BP. Of the 37 total hospital readmissions recorded in the 14 days after discharge, eight occurred in the intervention group and 29 in the control group (p<0.001).

“The number needed to treat to avoid one postnatal readmission for [elevated BP] was 5,” Kitt said.

Additional data showed that the intervention group had significant improvements in cardiac imaging parameters, including left ventricular mass, left ventricular ejection fraction, left ventricular global longitudinal strain, left atrial volume, left ventricular relative wall thickness, and average E/E ratio when compared with the control group.

“Improving postpartum BP control impacts short-to-medium term BP control that persists after medications are stopped” and leads to more favourable cardiac structure and function, Kitt explained.

The findings, he added, indicate that the postpartum period may be a “critical window” to reduce long-term risk.

POP-HT involved 220 women (mean age 32.6 years) who had hypertensive pregnancies, among whom 40 percent had gestational hypertension and 60 percent had pre-eclampsia. The intervention group included 112 women, while the control group included 108 women.

The trial is the first to show that “BP interventions in first few weeks after pregnancy can have long-term benefits,” highlighting a potential need for “a paradigm shift in the way women affected by hypertensive pregnancy are managed postnatally,” Kitt said.