: High quality evidence to inform the management of postpartum hypertension, including
the optimal blood pressure (BP) threshold to initiate therapy, is lacking. Randomized
trials have been conducted in pregnancy but there are no published trials to guide
management in the postpartum period.
: We conducted this randomized controlled trial to test our hypothesis that initiating
antihypertensive therapy in the postpartum period at a threshold of 140/90 mmHg would
result in less maternal morbidity than initiating therapy at a threshold of 150/95
: We performed a pragmatic multi-centered randomized controlled trial of patients aged
18-55 with postpartum hypertension. Patients with chronic hypertension, gestational
hypertension, and preeclampsia without severe features were randomized to one of two
BP thresholds to initiate treatment: persistent BP ≥ 150/95 mmHg (institutional standard
or “liberal control” group) or ≥ 140/90 mmHg (intervention or “tight control” group).
Our primary outcome was composite maternal morbidity defined as: severe hypertension
(BP ≥ 160/110 mmHg) or preeclampsia with severe features, the need for a second antihypertensive
agent, postpartum hospitalization > 4 days, and maternal adverse outcome secondary
to hypertension as evidenced by pulmonary edema, acute kidney injury (creatinine level
≥ 1.1 mg/dl), cardiac dysfunction (e.g. elevated brain natriuretic peptide level)
or cardiomyopathy, posterior reversible encephalopathy syndrome (PRES), cerebrovascular
accident, or admission to an intensive care unit. Secondary outcomes included hospital
readmission for hypertension, persistence of hypertension beyond 14 days, medication
side effects, and time to BP control. We calculated that 256 women would provide 90%
power to detect a relative 50% reduction in the primary outcome from 36% in the standard
BP threshold group to 18% with a two-sided alpha set at 0.05 for significance. Data
was analyzed using R statistical software.
: 256 patients were randomized including 128 to the “tight control” group (140/90 mmHg)
and 128 to the “liberal control” group (150/95 mmHg). Patients in the “tight control”
group had a higher BMI at delivery (37.1 ± 9.4 vs 34.9 ± 8.1 p= 0.04); otherwise,
demographic and obstetric characteristics were similar between groups. The rate of
the primary outcome was similar between groups (8.6 % vs 11.7%, p= 0.41; RR 0.73,
95% CI 0.35 to 1.53). The rates of all secondary outcomes and the individual components
of the primary and secondary outcome measures were also similar between groups.
: In the postpartum period, initiation of antihypertensive therapy at a lower BP threshold
of 140/90 mmHg did not decrease maternal morbidity or improve outcomes compared to
a threshold 150/95 mmHg.