Postpartum hypertension (PPHTN), defined as elevated blood pressure after childbirth, affects approximately 20% of women after delivery. Its incidence has been increasing in parallel with rising maternal age and higher rates of obesity among pregnant individuals [1]. PPHTN can occur de novo or in women with a history of hypertension. However, the risk of postpartum hypertension is known to be higher among women who have experienced hypertensive disorders of pregnancy (HDP), such as chronic hypertension, preeclampsia, eclampsia, and gestational hypertension [2,3]. While HDP is known to be a leading cause of morbidity and mortality [2,4], PPHTN is particularly concerning, contributing to over 70% of deaths related to hypertension during the postpartum period [5].

HDPs are common complications in pregnancy and predispose individuals to stroke, kidney disease, coronary heart disease, later development of chronic hypertension [4,6]. Women with HDPs face nearly a three-fold higher risk of cardiovascular-related complications compared to non-hypertensive women [7]. Given these elevated risks, the American Heart Association (AHA) and the American College of Obstetricians and Gynecologists (ACOG) recognize the postpartum period as a critical window for blood pressure management and cardiovascular risk assessment to improve long-term heart health [8]. Accordingly, ACOG recommends that individuals with HDPs receive an early postpartum evaluation within 7‐10 days of delivery, in addition to the routine 6-week postpartum visit [9]. However, attendance to postpartum visits is low, with nearly half of women missing their 6-week postpartum visit [10], due to systemic challenges with limited parental leave from work, childcare barriers, transportation barriers, scheduling barriers, and limited support networks [11-14]. Insurance plans in the United States may also not be required to fully cover additional visits outside of the routine postpartum visit (at 6 wk) for uncomplicated pregnancies [15], meaning that most women have limited or no contact with their health care providers in the weeks between hospital delivery discharge and the routine 6-week postpartum visit [16,17]. Although blood pressure in hypertensive pregnancies is generally expected to normalize by day 7 postpartum, pregnancy-related hypertension may persist throughout the postpartum period, extending beyond the early postpartum period [18]. Despite these recommendations, postpartum follow-up visits remain suboptimal [9,19]. Less than 50% of women with HDP attend at least one postpartum visit in the six weeks following delivery [9]. Digital health interventions that include remote monitoring therefore, present an important opportunity to facilitate regular blood pressure assessment in this high-risk population at a time when risk is elevated and when health care system engagement and communication with clinicians is limited.

Several studies have investigated strategies to enhance postpartum hypertension monitoring beyond scheduled clinic visits. One randomized clinical trial (RCT) used a Bluetooth-enabled remote device for daily blood pressure measurements over 6 weeks postpartum and observed systolic and diastolic pressures peaking around days 9‐12 before declining [2]. This study, however, included only women who developed de novo postpartum hypertension. RCTs among women with previously diagnosed gestational diabetes and preeclampsia showed improved diastolic BP readings [20]. Racial differences in PPHTN resolution have also been documented, with non-Black women showing faster resolution than Black women [21]. Additionally, a specialized postpartum hypertension clinic was established to improve detection and management among patients with severe HDPs [19]. While the clinic identified numerous untreated hypertensive cases missed by standard care, the median time to the first visit was 13 weeks postpartum, highlighting a significant gap in early monitoring. Further work by Socrates et al evaluated the acceptability of two telemonitoring strategies (a smartphone app and a programmed Excel spreadsheet) [22]. Both were well-received, though most participants preferred the smartphone-based option.

Research on hypertension trajectories among women at high risk for postpartum hypertension using digital health remote monitoring tools remains limited. As hypertension can develop or emerge quickly in this population, and in-person clinical assessment opportunities are limited in the 6-week period between delivery hospitalization discharge and the 6-week routine follow up visit, this population is ideally situated to potentially benefit from remote hypertension monitoring using technologies that allow for patient-reported data to be communicated with their healthcare providers. A useful strategy for collection of real-time data using repeated measures is Ecological Momentary Assessment (EMA) [23], which has been deployed to investigate trajectories of blood pressure as well as other physical and mental health symptoms that are subject to develop or change within a defined time period [24,25]. This study evaluates the course of hypertension status among women who underwent frequent blood pressure monitoring via a smartphone app by leveraging an EMA approach in combination with clinical team follow-up when positive screening for hypertension is detected from a participant. The primary objective is to assess within- and between-person changes in hypertension status over the first 6 weeks postpartum using a smartphone-based ecological momentary assessment protocol. The secondary objective is to characterize the trajectory of hypertension indicators across the 6-week period and to compare hypertension screening results from week one and week six within participants. The findings will enhance understanding of how digital health-based remote monitoring influences hypertension outcomes among postpartum women engaged in a smartphone-based intervention.

The study was funded in July of 2021 and data collection was initiated in November of 2021. Data collection for this study has been completed as of June 2025, per protocol, though data continues to be collected for the parent study from which this hypertension assessment component is derived. The parent study assesses a host of physical and mental health conditions among postpartum women with different risk factors and clinical histories. Data analysis is expected to be completed by Spring 2026. Publication of results are planned for Summer of 2026.

Our study will be among the few to evaluate the trajectory of hypertension and blood pressure via remote digital health monitoring in the postpartum period. It will provide insight into whether this approach is associated with detection of hypertension outcomes among postpartum women whose blood pressure was regularly tracked through a smartphone-based system. We hypothesize that hypertension will be detected in some participants throughout the monitoring period via positive screens for high BP and hypertension-related symptoms, but we anticipate that a greater proportion of positive hypertension screens will be detected in the first two weeks postpartum relative to the final weeks of the postpartum monitoring period.

According to ACOG, women with hypertensive disorders of pregnancy should have their BP assessed within 72 hours and again between 7 and 10 days after delivery [9,29]. Prior research also indicates that remote BP monitoring is an acceptable approach to new mothers [29]. Most existing studies on the effectiveness of remote BP monitoring have been randomized clinical trials or feasibility and implementation studies [20]. These investigations found that participation in remote BP monitoring was associated with nearly twice the likelihood of recording at least one BP measurement within 10 days postpartum as accessible to the treating healthcare provider. More than 80% of participants also reported satisfaction with their postpartum care when using home BP monitoring. Additionally, RCTs have demonstrated meaningful improvements in diastolic blood pressure among women with prior gestational diabetes or preeclampsia during the postpartum period [20].

Previous studies have reported reduced hospital readmission rates among women participating in similar remote BP monitoring interventions [30,31], though the trajectory of hypertension positive screens from remote monitoring interventions is not well characterized. This gap is clinically meaningful as the highest risk for adverse hypertension outcomes is in the postpartum period covered by our remote BP monitoring period, where there are also the fewest opportunities for insurance-covered postpartum healthcare visits between the delivery discharge and the routine 6-week follow up visit. Our study will contribute to growing evidence by fully characterizing hypertension trajectories through the postpartum period and we plan to use this data to inform investigation of the value and effectiveness of remote blood pressure monitoring delivered through mobile app by also assessing clinical outcomes from acute hypertension-related events as well as health service use and economic outcomes.

The strengths of the study include a rigorous recruitment strategy, retention strategy to mitigate potential losses to follow up, well-tested smartphone app, robust clinician involvement when potential hypertension is detected (ie, safety monitoring for participants), and a pre-specified analytical protocol to improve transparency. There are limitations to consider, including the potential for selection bias as we recruited only participants with a history of hypertension, such as preeclampsia, eclampsia, or gestational hypertension, or those with a current or prior elevated blood pressure reading (≥140/90), rather than recruitment of all postpartum women presenting for delivery of an infant. Consequently, our findings may not be generalizable to all postpartum women, including those who develop de novo postpartum hypertension. Although hypertension information was self-reported, patients submitted their blood pressure responses in real time, which helps minimize recall-related bias, but this strategy is subject to limitations of bias related to measurement error (ie, if the participant misunderstands the question or enters in their BP readings incorrectly).

Our study will strengthen understanding of blood pressure trajectories among high-risk postpartum women whose blood pressure is frequently monitored through a smartphone app Findings will provide evidence to support whether widespread implementation of this digital health surveillance approach to improve hypertension outcomes in maternal health, especially in the postpartum period, is clinically warranted. Publication of study findings are planned to be disseminated via a scientific journal in the JMIR network.