COMMITTEE ON PRACTICE BULLETINS—OBSTETRICS Practice Bulletin #203: Chronic Hypertension in Pregnancy. American College of Obstetricians and Gynecologists. Obstet Gynecol 2019;133:e26-50. Full text of Practice Bulletin #203 is available to ACOG members at http://www.acog.org/Resources-and-Publications/Practice-Bulletins/Committee-on-Practice-Bulletins-Obstetrics/Chronic-Hypertension-Pregnancy
Chronic Hypertension in Pregnancy Chronic hypertension is present in 0.9-1.5% of pregnant women (1) and may result in significant maternal, fetal, and neonatal morbidity and mortality. The rate of maternal chronic hypertension increased by 67% from 2000 to 2009, with the largest increase (87%) among African American women. This increase is largely secondary to the obesity epidemic and increasing maternal age (1,2). The trend is expected to continue.
The purpose of this document is to clarify the criteria used to define and diagnose chronic hypertension before or during pregnancy, to review the effects of chronic hypertension on pregnancy and vice versa, and to appraise the available evidence for management options. The purpose of these revised best practice recommendations is to provide a rational approach to chronic hypertension in pregnancy based on new research and relevant pathophysiologic and pharmacologic considerations.
Taking a rational approach to hypertension in the pregnant patient
The new American College of Obstetricians and Gynecologists (ACOG) Practice Bulletin on chronic hypertension in pregnancy1 replaces the prior ACOG task force hypertension in pregnancy report from 2013, which covered the full range of hypertensive diseases in pregnancy in an extremely thorough way. However, several factors prompted a needed update with a dedicated focus on chronic hypertension in pregnancy, particularly the new recommendations issued by the American College of Cardiology (ACC) and the American Heart Association (AHA) on the diagnosis and management of hypertensive disease in adults.2
Chronic hypertension in pregnancy is defined as any one of the following:
- Hypertension diagnosed or present before pregnancy, whether or not a woman is on antihypertensive medication
- Elevated blood pressure prior to 20 weeks of gestation on two occasions at least 4 hours apart. For the purposes of this diagnosis, a threshold of 140 mm Hg systolic or 90 mm Hg diastolic or both is used.
The basic core of these recommendations is unchanged from the ACOG task force report. However, it is unclear how to align the recent ACC/AHA guidelines2 with these pregnancy-related recommendations. The ACC/AHA criteria for diagnosing hypertension in adults now classify blood pressure into four categories based on blood pressure results, with stage I hypertension (and recommendation for treatment) starting at a lower blood pressure threshold than we typically use for pregnancy, systolic blood pressure of 130 to 139 mm Hg or diastolic blood pressure of 80 to 89 mm Hg.
While there is no consensus on how to apply the ACC/AHA recommendations to pregnancy, there does not appear to be benefit to initiating antihypertensive medication during pregnancy or low-dose aspirin for preeclampsia prevention for women who meet criteria for stage I hypertension during pregnancy based on a recent secondary analysis of a multicenter randomized controlled trial.3 However, data are limited on outcomes and preventative measures in women with stage I chronic hypertension. Therefore, according to ACOG, it is reasonable to continue managing patients who met the criteria for a diagnosis of hypertension based on ACC/AHA recommendations (including stage I hypertension) prior to pregnancy as chronically hypertensive during pregnancy.
The bulletin also addresses another hot diagnosis: white coat hypertension. Women with white coat hypertension are hypertensive during office visits but otherwise normotensive. They should be observed carefully during pregnancy as they are at increased risk of developing preeclampsia and gestational hypertension.4 Ambulatory blood pressure monitoring may be helpful when making decisions about starting antihypertensive medications in these patients.
The author reports no potential conflicts of interest with regard to this article.
ACOG ABSTRACT REFERENCES
- Bateman BT, Bansil P. Hernandez-Diaz S, Mhre JM, Callaghan WM, Kuklina EV. Prevalence, trends, and outcomes of chronic hypertension: a nationwide sample of delivery admissions. Am J Obstet Gynecol 2012;206:134.e1-8
- Martin JA, Hamilton BE, Ventura SJ, Osterman MJ, Kirmeyer S, Mathews TJ, et al. Births: final data for 2009. Natl Vital Stat Rep 2011;60:1-70.
- Chronic hypertension in pregnancy. ACOG Practice Bulletin No. 203. American College of Obstetricians and Gynecologists. Obstet Gynecol. 2019;133:e26-e50.
- Whelton PK, Carey RM, Aranow WS, Casey DE Jr., et al. 2017 ACC/AHA/AAPA/ABC/ACPM/AGS/APhA/ASH/ASPC/NMA/PCNA guideline for the prevention, detection, evaluation, and management of high blood pressure in adults: a report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines. J Am Coll Cardiol. 2018;71:e127-248.
- Sutton EF, Hauspurg A, Caritis SN, Powers RW, Catov JM. Maternal outcomes associated with lower range stage I hypertension [preprint]. Obstet Gynecol. 2018.
- Brown MA, Mangos G, Davis G, Homer C. The natural history of white coat hypertension during pregnancy. BJOG. 2005;112:601-606