Delivery at 39 Weeks Optimal for Hypertensive Pregnancies

TOPLINE:

Among pregnant patients with chronic hypertension, delivery at 39 weeks of gestation provides an optimal balance between stillbirth risk and neonatal outcomes. Analysis of 227,977 term singleton deliveries shows consistent findings across different patient subgroups.

METHODOLOGY:

• A population-based retrospective cohort study analyzed 227,977 nonanomalous singleton term births in the United States from 2014 to 2018 among patients with chronic hypertension.
• Researchers excluded pregnancies with superimposed preeclampsia, eclampsia, pregestational diabetes, and deliveries occurring before 37 weeks or at 43 or more weeks of gestation.
• Analysis compared rates of stillbirth, infant death within 1 year of life, and neonatal morbidity at each week of term pregnancy.
• Neonatal morbidity was defined as a composite of neonatal intensive care unit admission, ventilation for 6 hours or longer, a low 5-minute Apgar score (≤ 3), and seizures.

TAKEAWAY:

• The rate of stillbirth per 10,000 ongoing pregnancies increased with gestational age and was lowest at 38 weeks (6.5; 95% CI, 5.4-7.7).
• Rates of infant death and neonatal morbidity were lowest at 40 weeks (18.0/10,000 live births; 95% CI, 13.7-23.6) and 39 weeks (637/10,000 live births; 95% CI, 619-654), respectively.
• At 39 weeks of gestation, the risk for delivery was lower (651/10,000; 95% CI, 633-670) than the composite risk for expectant management (750/10,000; 95% CI, 720-781).
• According to the authors, findings were consistent for non-Hispanic Black patients and pregnancies complicated by fetal growth restriction.

IN PRACTICE:

“To prevent one case of stillbirth, infant death, or neonatal morbidity, an estimated 101 patients with chronic hypertension would need to deliver at 39 weeks of gestation as opposed to 40 weeks. Given the approximately 45,000 patients with chronic hypertension who deliver at term each year in the United States, a policy of delivery at 39 weeks of gestation theoretically would prevent 450 adverse perinatal events per year,” wrote the authors of the study.

SOURCE:

The study was led by Ira Hamilton, James Liu, Labeena Wajahat, and Robert Rossi, University of Cincinnati College of Medicine in Cincinnati. It was published online in O&G Open.

LIMITATIONS:

According to the authors, the study could not stratify chronic hypertension based on medication use, number of medications, or degree of control. The researchers note that exact timing of delivery in weeks and days was not reported, limiting precise understanding of optimal delivery timing. Additionally, the study could not examine rates of neonatal morbidity and mortality in patients who developed superimposed preeclampsia during expectant management.

DISCLOSURES:

The authors did not report any potential conflicts of interest.

This article was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.