Treatment for Mild Chronic Hypertension during Pregnancy
The New England Journal of Medicine (NEJM): Published
on April, 2022
Antihypertensive treatment during
pregnancy reduces the frequency of severe hypertension (blood pressure,
≥160/110 mm Hg) but has not been shown to improve maternal, fetal, or neonatal
outcomes and has been associated with an increased risk of
small-for-gestational-age birth weight.
Thus, treatment recommendations for
pregnant women with chronic hypertension is unclear
whether to withhold antihypertensive medication until the increase in blood
pressure is severe or to continue the patient’s previously established therapy.
To evaluate the benefits and safety
of pharmacologic antihypertensive therapy during pregnancy, authors designed a
randomized trial involving women with mild chronic hypertension, a condition
that is estimated to affect 70 to 80% of pregnant women with chronic
hypertension.
TAKE-HOME MESSAGE
In this open-label multicenter
randomized trial involving 2408 pregnant women with mild chronic hypertension
(BP <160/100 mm Hg), treatment with antihypertensive medications
recommended for use in pregnancy (target BP, <140/90 mm Hg) was associated
with a substantial reduction in the incidence of the primary composite outcome
of preeclampsia with severe features, medically indicated preterm birth,
placental abruption, and fetal or neonatal death.
No significant difference was observed in the risks of neonates having low birth weights for gestational age and serious maternal or neonatal complications between the treatment group and the control group.
CONCLUSIONS
In pregnant women with mild chronic
hypertension, a strategy of targeting a blood pressure of less than 140/90 mm
Hg was associated with better pregnancy outcomes without a significantly increased
risk of adverse maternal or neonatal events than a strategy of reserving
treatment only for severe hypertension, with no increase in the risk of
small-for-gestational-age birth weight.
American College of Obstetricians
and Gynecologists (ACOG) practice advisory
In response to the 2022 RCT,
The ACOG issued a practice advisory: “based on these findings,
the ACOG recommends utilizing 140/90 mm Hg as the threshold for initiation
or titration of medical therapy for chronic hypertension in pregnancy rather
than the previously recommended threshold of 160/110."
Summary
A 2022 RCT demonstrates improved outcomes with a good safety profile when pharmacologic treatment is used for non-severe chronic hypertension in pregnancy. Due to the quality of the 2022 RCT, The ACOG issued a practice advisory: “the ACOG now recommends treating non-severe hypertension in pregnancy with a blood pressure goal of <140/90 mm Hg utilizing 140/90 mm Hg as the threshold for initiation or titration of medical therapy for chronic hypertension in pregnancy rather than the previously recommended threshold of 160/110."
2022 RCT supporting treatment of
mild chronic hypertension in pregnancy
Overall, 2408 women with a
singleton pregnancy and mildly elevated blood pressure before 23 weeks of
gestation from 61 sites in the US were randomized to pharmacologic treatment
for blood pressure >140 mm Hg systolic or >90 mm
Hg diastolic or to pharmacologic treatment only for blood pressure >160
mm Hg systolic or >105 mm Hg diastolic.
The primary outcome was a composite of preeclampsia with severe features,
induction at <35 weeks gestation for medical reasons, placental abruption,
fetal death, or neonatal death.
The primary outcome was
statistically lower in the group treated for non-severe chronic hypertension in
pregnancy than in the severely elevated blood pressure group (30.2%
vs 37.0%).
The secondary outcomes included composites of
preeclampsia, preterm birth, and serious maternal or neonatal complications.
Secondary outcomes of preeclampsia
and preterm birth were also significantly lower in the non-severe chronic
hypertension group: preeclampsia (24.4% vs 31.1%) and preterm birth (27.5% vs
31.4%).
Safety was demonstrated with no
significant difference in Small for Gestational age (SGA() babies with cut off
<10% (11.2% vs 10.4%) or <5% (5.1% vs 5.5%).
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BACKGROUND
The benefits and safety of the
treatment of mild chronic hypertension (blood pressure, <160/100 mm Hg)
during pregnancy are uncertain. Data are needed on whether a strategy of targeting
a blood pressure of less than 140/90 mm Hg reduces the incidence of adverse
pregnancy outcomes without compromising fetal growth.
METHODS
In this open-label, multicenter,
randomized trial, we assigned pregnant women with mild chronic hypertension and
singleton fetuses at a gestational age of less than 23 weeks to receive
antihypertensive medications recommended for use in pregnancy (active-treatment
group) or to receive no such treatment unless severe hypertension (systolic
pressure, ≥160 mm Hg; or diastolic pressure, ≥105 mm Hg) developed (control
group). The primary outcome was a composite of preeclampsia with severe
features, medically indicated preterm birth at less than 35 weeks' gestation,
placental abruption, or fetal or neonatal death. The safety outcome was
small-for-gestational-age birth weight below the 10th percentile for
gestational age. Secondary outcomes included composites of serious neonatal or
maternal complications, preeclampsia, and preterm birth.
RESULTS
A total of 2408 women were enrolled
in the trial. The incidence of a primary-outcome event was lower in the
active-treatment group than in the control group (30.2% vs. 37.0%), for an
adjusted risk ratio of 0.82. The percentage of small-for-gestational-age birth
weights below the 10th percentile was 11.2% in the active-treatment group and
10.4% in the control group. The incidence of serious maternal complications was
2.1% and 2.8%, respectively, and the incidence of severe neonatal complications
was 2.0% and 2.6%. The incidence of any preeclampsia in the two groups was
24.4% and 31.1%, respectively, and the incidence of preterm birth was 27.5% and
31.4%.
CONCLUSIONS
In pregnant women with mild chronic
hypertension, a strategy of targeting a blood pressure of less than 140/90 mm
Hg was associated with better pregnancy outcomes than a strategy of reserving
treatment only for severe hypertension, with no increase in the risk of
small-for-gestational-age birth weight.
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