Abstract
SummaryBackgroundBlood pressure measurement is a marker of antenatal care quality. In well resourced settings, lower blood pressure cutoffs for hypertension are associated with adverse pregnancy outcomes. We aimed to study the associations between blood pressure thresholds and adverse outcomes and the diagnostic test properties of these blood pressure cutoffs in low-resource settings.MethodsWe did a secondary analysis of data from 22 intervention clusters in the Community-Level Interventions for Pre-eclampsia (CLIP) cluster randomised trials (NCT01911494) in India (n=6), Mozambique (n=6), and Pakistan (n=10). We included pregnant women aged 15–49 years (12–49 years in Mozambique), identified in their community by trained community health workers, who had data on blood pressure measurements and outcomes. The trial was unmasked. Maximum blood pressure was categorised as: normal blood pressure (systolic blood pressure [sBP] <120 mm Hg and diastolic blood pressure [dBP] <80 mm Hg), elevated blood pressure (sBP 120–129 mm Hg and dBP <80 mm Hg), stage 1 hypertension (sBP 130–139 mm Hg or dBP 80–89 mm Hg, or both), non-severe stage 2 hypertension (sBP 140–159 mm Hg or dBP 90–109 mm Hg, or both), or severe stage 2 hypertension (sBP ≥160 mm Hg or dBP ≥110 mm Hg, or both). We classified women according to the maximum blood pressure category reached across all visits for the primary analyses. The primary outcome was a maternal, fetal, or neonatal mortality or morbidity composite. We estimated dose-response relationships between blood pressure category and adverse outcomes, as well as diagnostic test properties.FindingsBetween Nov 1, 2014, and Feb 28, 2017, 21 069 women (6067 in India, 4163 in Mozambique, and 10 839 in Pakistan) contributed 103 679 blood pressure measurements across the three CLIP trials. Only women with non-severe or severe stage 2 hypertension, as discrete diagnostic categories, experienced more adverse outcomes than women with normal blood pressure (risk ratios 1·29–5·88). Using blood pressure categories as diagnostic thresholds (women with blood pressure within the category or any higher category vs those with blood pressure in any lower category), dose-response relationships were observed between increasing thresholds and adverse outcomes, but likelihood ratios were informative only for severe stage 2 hypertension and maternal CNS events (likelihood ratio 6·36 [95% CI 3·65–11·07]) and perinatal death (5·07 [3·64–7·07]), particularly stillbirth (8·53 [5·63–12·92]).InterpretationIn low-resource settings, neither elevated blood pressure nor stage 1 hypertension were associated with maternal, fetal, or neonatal mortality or morbidity adverse composite outcomes. Only the threshold for severe stage 2 hypertension met diagnostic test performance standards. Current diagnostic thresholds for hypertension in pregnancy should be retained.FundingUniversity of British Columbia, the Bill & Melinda Gates Foundation.
Highlights
Hypertension in pregnancy has traditionally been defined as a systolic blood pressure of at least 140 mm Hg or a diastolic blood pressure of at least 90 mm Hg, or both.[1]
Implications of all the available evidence Our findings suggest that there is an association between the American College of Cardiology and American Heart Association blood pressure thresholds and adverse pregnancy outcomes in low-income and middle-income countries (LMICs) settings, but there is no antenatal blood pressure threshold that is sensitive with regards to the adverse maternal, fetal, or neonatal outcomes studied, including datadriven cutoffs
The American College of Obstetricians and Gynecologists and WHO have retained a definition of blood pressure greater than or equal to 140/90 mm Hg for hypertension in pregnancy, several studies have reported a doseresponse relationship between increasing blood pressure and adverse pregnancy outcomes, across gestational ages;[3,4] these findings provide potential support for the redefinition of hypertension in pregnancy
Summary
Hypertension in pregnancy has traditionally been defined as a systolic blood pressure (sBP) of at least 140 mm Hg or a diastolic blood pressure (dBP) of at least 90 mm Hg, or both.[1]. In 2017, the American College of Cardiology and American Heart Association recommended lowering. Published Online July 5, 2021 https://doi.org/10.1016/ S2214-109X(21)00219-9. Academy of Higher Education and Research’s J N Medical. Belagavi, Karnataka, India (Prof M B Bellad MD, Prof S S Goudar MD);. S Nijalingappa Medical College, Hanagal Shree Kumareshwar Hospital and Research Centre, Bagalkote, Karnataka, India (Prof A A Mallapur MD); Centre for Global Child Health, Hospital for Sick Children, Toronto, ON, Canada (Prof Z A Bhutta)
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