Treatment for Mild Chronic Hypertension During Pregnancy
abstract
This abstract is available on the publisher's site.
Access this abstract nowBACKGROUND
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 (95% confidence interval [CI], 0.74 to 0.92; P<0.001). 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 (adjusted risk ratio, 1.04; 0.82 to 1.31; P = 0.76). The incidence of serious maternal complications was 2.1% and 2.8%, respectively (risk ratio, 0.75; 95% CI, 0.45 to 1.26), and the incidence of severe neonatal complications was 2.0% and 2.6% (risk ratio, 0.77; 95% CI, 0.45 to 1.30). The incidence of any preeclampsia in the two groups was 24.4% and 31.1%, respectively (risk ratio, 0.79; 95% CI, 0.69 to 0.89), and the incidence of preterm birth was 27.5% and 31.4% (risk ratio, 0.87; 95% CI, 0.77 to 0.99).
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.
Click on any of these tags to subscribe to Topic Alerts. Once subscribed, you can get a single, daily email any time PracticeUpdate publishes content on the topics that interest you.
Visit your Preferences and Settings section to Manage All Topic Alerts
Additional Info
Treatment for Mild Chronic Hypertension during Pregnancy
N. Engl. J. Med 2022 Apr 02;[EPub Ahead of Print], AT Tita, JM Szychowski, K Boggess, L Dugoff, B Sibai, K Lawrence, BL Hughes, J Bell, K Aagaard, RK Edwards, K Gibson, DM Haas, L Plante, T Metz, B Casey, S Esplin, S Longo, M Hoffman, GR Saade, KK Hoppe, J Foroutan, M Tuuli, MY Owens, HN Simhan, H Frey, T Rosen, A Palatnik, S Baker, P August, UM Reddy, W Kinzler, E Su, I Krishna, N Nguyen, ME Norton, D Skupski, YY El-Sayed, D Ogunyemi, ZS Galis, L Harper, N Ambalavanan, NL Geller, S Oparil, GR Cutter, WW AndrewsFrom MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
Treatment of non-severe chronic hypertension in pregnancy
The standard of care before a 2022 RCT has been to only treat severely elevated blood pressures for chronic hypertension in pregnancy.1 Some have been concerned that the treatment of non-severely elevated blood pressures could lead to hypoperfusion of the placenta, which puts the fetus at risk for fetal growth restriction (FGR) or stillbirth.
A 2018 Cochrane Review found that the treatment of non-severe chronic hypertension decreased the risk of developing severe hypertension (RR, 0.49; 95% CI, 0.40–0.60; 20 RCTs; 2558 women); however, it did not decrease the risk of preeclampsia (aRR, 0.92; 95% CI, 0.75–1.14; 23 RCTs; 2851 women), fetal or neonatal death (aRR 0.72; 95% CI, 0.50–1.04; 29 RCTs; 2265 women), or preterm birth at <37 weeks of gestation (aRR, 0.96; 95% CI, 0.83–1.12; 15 RCTs; 2141 women).1 In addition to no significant increase in fetal or neonatal death, there was no increase in the delivery of small for gestational age (SGA) babies (aRR 0.96; 95% CI, 0.78–1.18; 21 RCTs; 2686 babies).2
2022 RCT supporting treatment of mild chronic hypertension in pregnancy3
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 secondary outcomes included composites of preeclampsia, preterm birth, and serious maternal or neonatal complications. The safety was evaluated by monitoring for small for gestational age (<10 percentile and <5 percentile) babies at birth.3
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%; aRR, 0.82; NNT, 14–15). Secondary outcomes of preeclampsia and preterm birth were also significantly lower in the non-severe chronic hypertension group: preeclampsia (24.4% vs 31.1%; RR, 0.79) and preterm birth (27.5% vs 31.4%; RR, 0.87). Safety was demonstrated with no significant difference in SGA babies with cut off <10% (11.2% vs 10.4%; aRR, 1.04; P = 0.76) or <5% (5.1% vs 5.5%; RR, 0.92).3
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."1 However, the ACOG advisory points out that a target blood pressure lower limit is not established and there may be a blood pressure below which the risk of FGR increases. Additionally, because of the increased FGR risk with chronic hypertension regardless of treatment, a third trimester growth ultrasound is recommended.1 The 2022 RCT is seen as superior to previous studies because of the large number of patients diagnosed with chronic hypertension on medications at the start of the trial, the large number enrolled in early pregnancy, and the racial and ethnic diversity of the study participants.1
Summary
A 2022 RCT demonstrates improved outcomes with a good safety profile when pharmacologic treatment is used for non-severe chronic hypertension in pregnancy. This counters a 2018 Cochrane Review which included over 20 RCTs and over 2000 women for each of the outcomes evaluated and ACOG’s previous clinical guidance. Due to the quality of the 2022 RCT, The ACOG now recommends treating non-severe hypertension in pregnancy with a blood pressure goal of <140/90 mm Hg.
References