A new definition of gestational hypertension? New-onset blood pressures of 130 to 139/80 to 89 mm Hg after 20 weeks of gestation.

BACKGROUND

Diagnostic criteria for hypertensive disorders in pregnancy have historically been based on the American Heart Association and American College of Cardiology's definition of hypertension, previously defined as a blood pressure of ≥140/90 mm Hg. With the recent redefinition of hypertension, blood pressures of 130 to 139/80 to 89 mm Hg are now considered abnormal.

OBJECTIVE

In this study, we aimed to test whether the new-onset blood pressure elevations of 130 to 139/80 to 89 mm Hg after 20 weeks of gestation in previously normotensive women are associated with increased risk for adverse pregnancy outcomes, specifically the development of hypertensive disorders in pregnancy.

STUDY DESIGN

We performed a retrospective cohort study at a single tertiary care center of all women who delivered singleton gestations after 20 weeks of gestation from January 01, 2014, to June 08, 2016. Normotensive patients were defined as having maximum blood pressure of <130/80 mm Hg before 20 weeks of gestation and no previous diagnosis of chronic hypertension. Patients who remained normotensive for the remainder of pregnancy were then compared with patients who developed new-onset blood pressure elevations of 130 to 139/80 to 89 mm Hg after 20 weeks of gestation before delivery admission. The primary outcome was the development of a hypertensive disorder in pregnancy at hospital admission or during delivery. Clinical outcomes were assessed using χ test and multivariable logistic regression.

RESULTS

Of the 2090 normotensive women from our cohort who were analyzed, 1318 (63.0%) remained normotensive for their entire antenatal course before delivery admission and 772 (37.0%) had new-onset blood pressure elevations between 130 and 139/80 and 89 mm Hg. Women with new-onset blood pressure elevations between 130 and 139/80 and 89 mm Hg after 20 weeks of gestation have a significantly increased risk for developing a hypertensive disorder in pregnancy at admission or during delivery (adjusted relative risk, 2.41; 95% confidence interval, 2.02-2.85) including an almost 3-fold increased risk for preeclampsia with severe features, even after adjusting for confounders. There were no differences in other secondary obstetrical outcomes.

CONCLUSION

Normotensive women with new-onset blood pressures elevations between 130 and 139/80 and 89 mm Hg after 20 weeks of gestation are more likely to experience hypertensive disorders in pregnancy and preeclampsia with severe features at or during their delivery hospitalization. These more modest blood pressure elevations may be an early indicator of disease and call into question our current blood pressure threshold for diagnosis of hypertensive disorders in pregnancy.