Recently published evidence has demonstrated that tight blood pressure targets in pregnancy are associated with improved maternal outcomes and are not associated with increased risk for the unborn baby. CCOPMM have observed an increase in maternal and fetal morbidity associated with delayed treatment of elevated blood pressure.
Background
Hypertension in pregnancy is associated with increased risk of adverse outcome for mothers and babies. Recommendations for treatment thresholds and targets have varied both internationally and within Australia. Treatment of severe hypertension (i.e., blood pressure > 160/110) has been widely recommended for many years, however treatment of mild-moderate hypertension has been less widely endorsed(1).
In recent years, there has been recognition of the long-term health benefits of treating mild hypertension in all adults. Both the American Heart Association and the European Society of Hypertension recommend the treatment of blood pressure in adults > 140/90(2). In the pregnant population, a recently published large, randomised control trial demonstrated significant reduction in maternal and neonatal harm with treatment of mild hypertension(3). This study demonstrated that targeting maternal blood pressure <140/90 reduced the incidence of severe pre-eclampsia and medically indicated pre-term birth, without increased risk of low birth weight infants(3).
Advice for clinicians
- Clinicians should assess and record the maternal blood pressure at every pregnancy visit.
- Women with pre-existing hypertension should not cease anti-hypertensive medications, however clinicians should ensure that these women are on pregnancy-safe medications.
- Women with a systolic blood pressure > 140 or a diastolic blood pressure > 90 should be screened for pre-eclampsia and clinicians should commence therapy to target a blood pressure < 140/90
- When treating hypertension in pregnancy, women should continue to be monitored closely until delivery, and gestation specific fetal surveillance should be initiated.
References
- Lowe SA, Bowyer L, Lust K, et al. The SOMANZ Guidelines for the Management of Hypertensive Disorders of Pregnancy 2014. Aust N Z J Obstet Gynaecol. 2015;55(1):11-16. doi:10.1111/ajo.12253
- Whelton PK, Carey RM, Mancia G, Kreutz R, Bundy JD, Williams B. Harmonization of the American College of Cardiology/American Heart Association and European Society of Cardiology/European Society of Hypertension Blood Pressure/Hypertension Guidelines: Comparisons, Reflections, and Recommendations. Circulation. 2022;146(11):868-877. doi:10.1161/CIRCULATIONAHA.121.054602
- Tita AT, Szychowski JM, Boggess K, et al. Treatment for Mild Chronic Hypertension during Pregnancy. N Engl J Med. 2022;386(19):1781-1792. doi:10.1056/NEJMoa2201295