Effect of Self-monitoring of Blood Pressure on Diagnosis of Hypertension During Higher-Risk Pregnancy: The BUMP 1 Randomized Clinical Trial

Abstract

Importance: Inadequate management of elevated blood pressure (BP) is a significant contributing factor to maternal deaths. Self-monitoring of BP in the general population has been shown to improve the diagnosis and management of hypertension; however, little is known about its use in pregnancy.

Objective: To determine whether self-monitoring of BP in higher-risk pregnancies leads to earlier detection of pregnancy hypertension.

Design, setting, and participants: Unblinded, randomized clinical trial that included 2441 pregnant individuals at higher risk of preeclampsia and recruited at a mean of 20 weeks' gestation from 15 hospital maternity units in England between November 2018 and October 2019. Final follow-up was completed in April 2020.

Interventions: Participating individuals were randomized to either BP self-monitoring with telemonitoring (n = 1223) plus usual care or usual antenatal care alone (n = 1218) without access to telemonitored BP.

Main outcomes and measures: The primary outcome was time to first recorded hypertension measured by a health care professional.

Results: Among 2441 participants who were randomized (mean [SD] age, 33 [5.6] years; mean gestation, 20 [1.6] weeks), 2346 (96%) completed the trial. The time from randomization to clinic recording of hypertension was not significantly different between individuals in the self-monitoring group (mean [SD], 104.3 [32.6] days) vs in the usual care group (mean [SD], 106.2 [32.0] days) (mean difference, -1.6 days [95% CI, -8.1 to 4.9]; P = .64). Eighteen serious adverse events were reported during the trial with none judged as related to the intervention (12 [1%] in the self-monitoring group vs 6 [0.5%] in the usual care group).

Conclusions and relevance: Among pregnant individuals at higher risk of preeclampsia, blood pressure self-monitoring with telemonitoring, compared with usual care, did not lead to significantly earlier clinic-based detection of hypertension.

Trial registration: ClinicalTrials.gov Identifier: NCT03334149.

Figure.. Eligibility, Randomization, and Data Availability for Self-monitoring for Hypertension Among Pregnant Individuals at Risk for Preeclampsia

^aScreening was conducted by research midwives reviewing clinical notes; therefore, the number of potentially suitable participants may underrepresent the true number. Higher risk of preeclampsia was defined by the relevant UK guidance at the time and included 1 or more of the following risk factors for pregnancy hypertension: age ≥40 years with a nulliparity pregnancy interval >10 years, family history of preeclampsia, history of preeclampsia or gestational hypertension, body mass index of ≥30 (calculated as weight in kilograms divided by height in meters squared), any stage of chronic kidney disease, twin pregnancy, prepregnancy diabetes, and autoimmune disease (eg, systemic lupus erythematosus or antiphospholipid syndrome). ^bIndicates 16 weeks 0 days to 24 weeks 0 days. ^cIndividuals who were randomized in error (3 in the self-monitoring group and 1 in the usual care group) were excluded from the analysis population. ^dFollow-up numbers include individuals eligible to be followed up (ie, not withdrawn or lost to follow-up) who completed questionnaires at that time. All available data were included in the analyses but some were available at only 1 follow-up point. For the self-monitoring group (n = 1223), 615 participants completed both 30-week and postnatal follow-up, 289 completed only 30-week follow-up, 79 completed only postnatal follow-up, and 240 completed neither follow-up. For the usual care group (n = 1218), 636 participants completed both 30-week and postnatal follow-up, 288 completed 30-week follow-up, 79 completed only postnatal follow-up, and 215 completed neither follow-up.