Screening for Hypertensive Disorders of Pregnancy: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force | Guidelines | JAMA

Hypertensive disorders of pregnancy include gestational hypertension; preeclampsia-eclampsia; and chronic hypertension with superimposed preeclampsia.1^,2 The incidence of hypertensive disorders of pregnancy has been steadily increasing over the last several decades, from 500 cases per 10 000 deliveries in 1993 to 1021 cases per 10 000 deliveries in 2016 to 2017, with more than half of these having a diagnosis of preeclampsia-eclampsia (555 cases per 10 000 deliveries).³ Between 2014 and 2017 hypertensive disorders of pregnancy were responsible for 6.8% of pregnancy-related deaths overall, with the majority of deaths (65%) occurring in the 6 weeks following delivery.^4,5 In addition to risks of mortality to pregnant individuals, hypertensive disorders of pregnancy contributes to pregnancy-related morbidity and risks to the fetus, including fetal growth restriction and indicated preterm delivery.^6–10

Hypertensive disorders of pregnancy account for a larger proportion of pregnancy-related mortality and morbidity among Black populations than among White populations.11^–16 Due to higher incidence and severity, alongside inequities in the quality of health care due to structural and systemic factors,^17,18 the risk of dying of preeclampsia-eclampsia complications is about 5 times greater for Black individuals (3.93 per 100 000 live births) than for White individuals (0.78 per 100 000 live births).^12,16 Hypertensive disorders of pregnancy are also a leading cause of pregnancy-related mortality (≈13% of deaths) among American Indian/Alaska Native people and contributes to higher pregnancy-related mortality among American Indian/Alaska Native persons compared with White persons (29.7 compared with 12.7 per 100 000 live births in 2007-2016).^7,11,19

In 2017, the US Preventive Services Task Force (USPSTF) recommended screening pregnant women for preeclampsia with blood pressure measurements throughout pregnancy (grade B).20 Routine screening for new-onset hypertension via office-based blood pressure measurement can identify individuals who develop hypertensive disorders of pregnancy, allowing for evidence-based interventions that reduce the risk of pregnancy complications for the pregnant individual and infant.^1,20,21 This review of comparative effectiveness studies sought evidence on potential refinements to recommended screening practice.

An analytic framework and 3 key questions (KQs) guided the evidence update (Figure 1). Detailed methods and results of this systematic review are available in the full evidence report.²³ This review examines the comparative effectiveness of different screening protocols for hypertensive disorders of pregnancy, including preeclampsia.

A search of MEDLINE and the Cochrane Central Register of Controlled Trials was conducted for literature published between January 1, 2014, and January 4, 2022 (eMethods in the Supplement). These searches were supplemented by examining reference lists of primary studies and reviews. ClinicalTrials.gov was searched for ongoing trials. From January 2022 through February 1, 2023, ongoing surveillance of the literature to identify new studies that might affect the review conclusions or interpretation of the evidence was conducted using article alerts and targeted searches of journals with high impact factors; we identified no new studies that would meet inclusion criteria for this review.

Studies were excluded if effects of changes to screening programs could not be separated from the effects of concurrent interventions (eg, patient education, service delivery model). Studies that evaluated the effectiveness of diagnostic testing or monitoring among people with hypertensive disorders of pregnancy, including those with chronic hypertension in pregnancy, were not eligible for inclusion. The definition of hypertensive disorders of pregnancy includes pregnant individuals with chronic hypertension. However, this review only included studies evaluating screening for new-onset hypertension because individuals entering pregnancy with a diagnosis of chronic hypertension would be subject to ongoing monitoring and assessment recommended for individuals with hypertensive disorders of pregnancy. Studies of the performance of risk prediction tools were not included in this review, although comparative effectiveness trials involving risk assessment would have been eligible for inclusion (eTable 1 in the Supplement).

Two investigators independently evaluated whether articles met the review inclusion criteria and rated the risk of bias of included studies following USPSTF procedures for assessing the internal validity of randomized clinical trials (RCTs) and nonrandomized studies of interventions (eTable 2 in the Supplement).²² Discrepancies were resolved through discussion and consultation with a third investigator as needed. Study data were extracted into structured forms and checked for errors by a second investigator. Included outcomes were mortality, morbidity related to hypertensive disorders of pregnancy, measures of health-related quality of life, and adverse events (including missed diagnosis). The strength of the overall body of evidence for each KQ was judged using an adaptation of the GRADE (Grading of Recommendations Assessment, Development, and Evaluation) Working Group approach.²⁴ The Evidence-based Practice Center adaptation²⁵ addresses 4 domains: consistency, precision, reporting bias, and study quality. Strength of evidence was independently assessed as “High,” “Moderate,” “Low,” or “Insufficient” by at least 2 investigators, with discrepancies resolved through consensus discussion. Given the limited number of studies and their clinical heterogeneity, we did not conduct any quantitative synthesis. Detailed results are available in the full evidence synthesis report.²³

The search identified 6316 titles and abstracts and 82 full-text articles (Figure 2). Six fair-quality studies, 5 RCTs^26–30 and 1 nonrandomized study with a historical control³¹ (N = 10 165) were included (Table 1). The studies compared usual screening with strategies involving home blood pressure measurement (2 studies, n = 2521), prenatal care schedules with less frequent office visits compared with the usual number (3 studies, n = 5203), and urine screening tests conducted for patients selected based on specific clinical indications, rather than routinely (1 study, n = 2441). Five of the studies^26,28–31 were included for examination of benefits of alternative screening strategies (KQ1, KQ2), and 1 study²⁷ of home blood pressure measurement screening was additionally included for harms (KQ3). All studies were conducted during the prenatal period, with no studies examining screening for new-onset hypertensive disorders of pregnancy during the postpartum period. Overall, the strength of the evidence was judged to be insufficient for nearly all comparisons and outcomes available (Table 2).

The effectiveness of home blood pressure measurement in addition to office-based measurement was addressed in 1 fair-quality RCT conducted in the UK (n = 2441).29 The BUMP 1 (Blood Pressure Monitoring in High Risk Pregnancy to Improve the Detection and Monitoring of Hypertension 1) trial examined the effect of home blood pressure measurement and automated feedback from a mobile-phone application as supplements to routine office-based prenatal care screening. The comparison group received routine office-based screening. Individuals were recruited into the trial based on an increased risk of a hypertensive disorder of pregnancy based on common clinical risk factors (eg, nulliparity, age, pregnancy, family history, previous preeclampsia, body mass index >30 [calculated as weight in kilograms divided by the square of height in meters], twin pregnancy, diabetes). The study population was reported as Asian or Asian British (10%), Black or Black British (8%), White (British, Irish, other) (74%), and “other or mixed” race and ethnicity (not specified by authors) (7%). Approximately 1 of 5 (17%) had a clinical history of a hypertensive disorder of pregnancy in a prior pregnancy, and a majority were nulliparous (61%). The study examined several serious maternal and infant health outcomes; none were statistically significant between study groups, but most were rare events with imprecise estimated effects. A composite outcome defined as 1 or more serious maternal health complications related to hypertensive disorders of pregnancy (eclampsia; transient ischemic attack; stroke; HELLP [hemolysis, elevated liver enzyme levels, low platelet count] syndrome; pulmonary edema; and liver, kidney, or hematologic involvement) was not statistically different between groups (relative risk [RR], 0.79 [95% CI, 0.40-1.55]). The primary study outcome, mean difference between groups in days to detection of hypertensive disorder of pregnancy, was less than 2 days (SD, 1.6) and not statistically significant (95% CI, −8.1 to 4.9). The BUMP 1 trial²⁹ and an additional RCT (n = 80)²⁷ met inclusion criteria for examining harms of home blood pressure measurement in addition to regular office-based screening (KQ3). Neither study reported differences in anxiety or health-related quality of life during pregnancy or postpartum for individuals using home blood pressure measurement devices.

We identified 3 fair-quality RCTs (n = 5203) that compared different prenatal visit schedules among individuals identified as at low risk for pregnancy complications.26^,28,30 Those in the intervention group were assigned to reduced prenatal care visit schedules (6-9 visits) relative to standard visit schedules (≈14 visits), thus receiving fewer in-office blood pressure measurements to screen for a hypertensive disorder of pregnancy, as well as other counseling and screening services. In all 3 of these trials, the difference in the overall number of visits between study groups was smaller than intended by the trial design, with the difference between groups ranging from 2.2 to 3.2 visits. The studies were underpowered for rare, serious health outcomes and reported no differences between study groups in preterm delivery, perinatal mortality, placental abruption, or postpartum hemorrhage; nor were there differences in the proportion diagnosed with preeclampsia. No differences in anxiety or depression were identified between groups receiving standard compared with reduced prenatal visit schedules.

We identified 1 fair-quality single nonrandomized study that compared a historical control group with routine urine screening at every prenatal visit vs screening only when clinically indicated (eg, based on weight loss, elevated blood pressure, urinary symptoms) (n = 2441).31 The study enrolled Black women (9%), Hispanic women (75%), White women (19%), and “others” without race and ethnicity information reported (6%). There was no difference in the proportion of individuals diagnosed with a hypertensive disorder of pregnancy after the transition to indicated urine screening only (RR, 1.00 [95% CI, 0.74-1.36]). There was a reduced risk of preterm delivery with indicated screening compared with the historical comparison group that underwent routine screening (RR, 0.64 [95% CI, 0.45-0.90]); no other differences in health outcomes were found. However, reviewers assessed this study as having considerable risk of bias owing to changes in the population and the health care setting over the course of the study.

This review did not find evidence that specific strategies for screening for hypertensive disorders of pregnancy in addition to or as an alternative to standard prenatal visit schedules with in-office blood pressure assessment improved health outcomes or led to earlier or increased detection relative to standard prenatal care. The available evidence on the comparative effectiveness of screening did not suggest that any specific features of screening programs improved health outcomes relative to standard prenatal care. However, the studies addressing these questions were few in number and were underpowered for important pregnancy health outcomes and potential harms of different screening programs. A 2022 literature review of screening for hypertensive disorders of pregnancy also examined evidence regarding prenatal visit schedules and the use of telehealth visits for routine antenatal care and similarly found limited evidence available for comparing different prenatal schedules and virtual care approaches for antenatal health care and their effects on health outcomes.32 Telehealth interventions using home blood pressure measurements could improve access to care and strengthen health care connections over the course of pregnancy, especially in settings that have instituted virtual care for some prenatal visits, but the evidence available to assess whether specific innovations involving telehealth might improve outcomes or lead to adverse or unintended consequences is limited. Whether telehealth could help address inequities in health also is uncertain. Evidence from natural experiments in telehealth-delivered prenatal care during the COVID-19 pandemic may stimulate further research and innovation.^33,34

None of the studies identified in this review had adequate power to evaluate outcomes specifically for American Indian/Alaska Native or Black persons, who are the US populations with the highest rates of hypertensive disorders of pregnancy. Few or none of the participants in the included studies were from these populations. Inequities in hypertensive disorders of pregnancy and related morbidity and mortality for Black individuals are well documented and persistent.35^,36 Several frameworks have been developed to describe the individual, interpersonal, community, and societal factors contributing to health inequities and the higher incidence of hypertensive disorders of pregnancy and greater disease severity and mortality among American Indian/Alaska Native and Black individuals.^17,37–40

Despite evidence that complications from missed diagnoses or emergent hypertensive disorders of pregnancy are known to arise postpartum and contribute to poor outcomes,41 none of the included studies evaluated hypertensive disorders of pregnancy screening in the postpartum period. Opportunities to be screened during the postpartum period may be limited due to clinician and insurance transitions, a focus on the neonate, and reduced continuity of support.^42–44 A 2019 systematic review that included 9 observational studies on postpartum monitoring of hypertensive disorders of pregnancy and gestational diabetes reported a pattern of lower rates of follow-up for Black and Hispanic people than White people in the 6 weeks after delivery.⁴² Routine screening during the postpartum period could be important for reducing health inequities, especially in light of emerging evidence that the risk of postpartum preeclampsia diagnosis is twice as high for non-Hispanic Black individuals compared with non-Hispanic White individuals.⁴⁵

Another area with limited research is the use of home blood pressure measurement to screen for new-onset hypertensive disorders of pregnancy. Although home blood pressure measurement and self-measurement have been used as part of management of care for individuals with diagnosed hypertensive disorder of pregnancy, limited evidence exists for its use as a primary screening tool. The single included trial evaluating supplemental home blood pressure measurement accompanied by automated feedback using a mobile-phone application reported null findings for health benefits but no harms associated with the intervention.29

Routine measurement of blood pressure during pregnancy has long been a standard of prenatal care.46 Innovations in screening programs involving changes to standard prenatal visit schedules, virtual visits, and telehealth applications, or the use of home blood pressure measurement, have the potential to influence pregnancy outcomes. Large, well-designed studies to refine prenatal and postpartum screening programs for individuals at different levels of risk for developing hypertensive disorders of pregnancy are needed, with attention to populations at increased risk for complications from hypertensive disorders of pregnancy. Establishing evidence-based screening practices will require large studies to evaluate changes to hypertensive disorders of pregnancy screening programs that could improve health outcomes without incurring harms.

Corresponding Author: Jillian T. Henderson, PhD, Kaiser Permanente Evidence-based Practice Center, Center for Health Research, Kaiser Permanente Northwest, 3800 N Interstate Ave, Portland, OR 97227 (Jillian.T.Henderson@kpchr.org).

Author Contributions: Dr Henderson had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis.

Concept and design: All authors.

Acquisition, analysis, or interpretation of data: Henderson, Webber, Vesco.

Drafting of the manuscript: Henderson.

Critical revision of the manuscript for important intellectual content: Webber, Thomas, Vesco.

Administrative, technical, or material support: Webber, Thomas.

Supervision: Henderson.

Conflict of Interest Disclosures: Dr Vesco reported receiving grants from Pfizer Independent Grants for Learning and Change Funding awarded to her institution for a project to develop and test a novel menopause curriculum for medial residents. No other disclosures were reported.

Funding/Support: This research was funded under contract 75Q80120D00004, Task Order 1, from the Agency for Healthcare Research and Quality (AHRQ), US Department of Health and Human Services.

Role of the Funder/Sponsor: Investigators worked with USPSTF members and AHRQ staff to develop the scope, analytic framework, and key questions for this review. AHRQ had no role in study selection, quality assessment, or synthesis. AHRQ staff provided project oversight; reviewed the report to ensure that the analysis met methodological standards; and distributed the draft for peer review. Otherwise, AHRQ had no role in the conduct of the study; collection, management, analysis, and interpretation of the data; and preparation, review, or approval of the manuscript findings. The opinions expressed in this document are those of the authors and do not reflect the official position of AHRQ or the US Department of Health and Human Services.

Additional Contributions: We gratefully acknowledge the following individuals for their contributions to this project: Iris R. Mabry-Hernandez, MD, MPH (AHRQ); current and former members of the USPSTF who contributed to topic deliberations; and Evidence-based Practice Center staff members Sarah I. Bean, MPH, Neon Brooks, PhD, and Melinda Davies, MAIS, for technical and editorial assistance at the Kaiser Permanente Center for Health Research. USPSTF members, peer reviewers, and federal partner reviewers did not receive financial compensation for their contributions.

Additional Information: A draft version of this evidence report underwent external peer review from 4 content experts (Kimberly D. Gregory, MD, MPH, Cedars-Sinai Medical Center; Laura A. Magee, MD, King’s College London; Alex Friedman Peahl, MD, MS, University of Michigan; Katherine Tucker, PhD, University of Oxford), and 3 federal partners (Centers for Disease Control and Prevention; the National Heart, Lung, and Blood Institute; and the National Institutes of Health Office of Research on Women’s Health). Comments were presented to the USPSTF during its deliberation of the evidence and were considered in preparing the final evidence review.

Editorial Disclaimer: This evidence report is presented as a document in support of the accompanying USPSTF recommendation statement. It did not undergo additional peer review after submission to JAMA.