39 Weeks May Be Optimal Delivery Time for Females with Chronic Hypertension: Study Finds

In a study published recently in the journal O&G Open, researchers found 39 weeks of gestation is optimal for delivery when chronic hypertension is a factor.

Researchers used U.S. Centers for Disease Control and Prevention birth records from 2014 to 2018, which included about 227,000 women, making it the largest study to date to look at delivery timing in pregnant moms with chronic hypertension.

Data shows 3% to 10% of pregnant women have hypertension, a vascular disorder that affects blood flow to the uterus and placenta and can impact the growth of a fetus. Chronic hypertension can lead to preeclampsia, preterm birth, stillbirth, low birth weight and newborn death after delivery.

The research concluded that among patients with chronic hypertension, delivery at 39 weeks provides the optimal balance between the risk of stillbirth associated with ongoing pregnancy and the risks of infant health issues or death associated with a birth before 39 weeks.

The research team also found the same optimal delivery timing in African American women, who are disproportionately impacted by chronic hypertension during pregnancy and are at higher risk for stillbirth and infant death.

“For every roughly 100 patients with chronic hypertension who deliver at 39 weeks instead of 40 weeks, we would expect to see one less stillbirth, infant death or adverse newborn outcome,” said corresponding author Robert Rossi, MD, associate professor in the Department of Obstetrics and Gynecology and director of the Division of Maternal-Fetal Medicine

Optimal delivery timing is essential, he explained, because the prevalence of chronic hypertension during pregnancy is increasing.

“In the future, it will also be important to study patients who are medicated for their chronic hypertension during pregnancy to see if they should also deliver at 39 weeks, or if earlier delivery is more beneficial to this specific group,” said Rossi.

Reference: Hamilton, Ira MD; Liu, James MD; Wajahat, Labeena MD; DeFranco, Emily A. DO, MS; Rossi, Robert MD. Optimizing Delivery Timing in Pregnant Patients With Chronic Hypertension at Term. O&G Open 1(4):p 050, December 2024. | DOI: 10.1097/og9.0000000000000050