Impact of the 2017 ACC/AHA Guideline for High Blood Pressure on Evaluating Gestational Hypertension-Associated Risks for Newborns and Mothers

Rationale: In 2017, the American College of Cardiology (ACC)/American Heart Association (AHA) released a new hypertension guideline for nonpregnant adults, using lower blood pressure values to identify hypertension. However, the impact of this new guideline on the diagnosis of gestational hypertension and the associated maternal and neonatal risks are unknown.

Objective: To estimate the impact of adopting the 2017 ACC/AHA guideline on detecting gestational blood pressure elevations and the relationship with maternal and neonatal risk in the perinatal period using a retrospective cohort design.

Methods and results: This study included 16 345 women from China. Systolic and diastolic blood pressures of each woman were measured at up to 22 prenatal care visits across different stages of pregnancy. Logistic and linear regressions were used to estimate associations of blood pressure categories with the risk of preterm delivery, early-term delivery, and small for gestational age, and indicators of maternal liver, renal, and coagulation functions during pregnancy. We identified 4100 (25.1%) women with gestational hypertension using the 2017 ACC/AHA guideline, compared with 4.2% using the former definition. Gestational hypertension, but not elevated blood pressure (subclinical blood pressure elevation), was significantly associated with altered indicators of liver, renal, and coagulation functions during pregnancy for mothers and increased risk of adverse birth outcomes for newborns; adjusted odds ratios (95% CIs) for gestational hypertension stage 2 were 2.23 (1.18-4.24) for preterm delivery, 2.05 (1.67-2.53) for early-term delivery, and 1.43 (1.13-1.81) for small for gestational age.

Conclusions: Adopting the 2017 ACC/AHA guideline would result in a substantial increase in the prevalence of gestational hypertension; subclinical blood pressure elevations during late pregnancy were not associated with increased maternal and neonatal risk in this cohort. Therefore, the 2017 ACC/AHA guideline may improve the detection of high blood pressure during pregnancy and the efforts to reduce maternal and neonatal risk. Replications in other populations are required.