How timed birth affects preeclampsia rates

How timed birth affects preeclampsia rates

Timed birth may prevent over half of preeclampsia cases, according to a recent study published in Hypertension.

Preeclampsia, the leading cause of maternal death worldwide, is defined as high blood pressure 140/90 mm Hg or higher. About 1 in 25 pregnancies in the United States are affected by preeclampsia, with diagnoses usually occurring after 20 weeks of pregnancy.

Maternal symptoms of preeclampsia include vision changes, headaches, and hand, foot, or eye swelling. Infants may also experience a change in well-being, and mothers with preeclampsia will experience increased risk of heart complications later in life.

Preeclampsia most often occurs at-term, a period between 37 and 42 weeks of pregnancy. At-term preeclampsia is 3 times more common the preterm preeclampsia and leads to more complications for mothers and babies.

There are limited treatment options with proven safety and efficacy, despite preeclampsia screening being routine during pregnancy. Preterm preeclampsia risk is more than halved by low doses of aspirin, but no effect is seen for at-term preeclampsia.

Induced labor and Cesarean deliveries are timed birth strategies used for various reasons but are not common for preventing at-term preeclampsia. To determine the effectiveness of timed birth, investigators analyzed health records of almost 90,000 pregnancies across more than a decade.

Of 57,131 pregnancies with health records at 11 to 13 weeks, 1138 had at-term preeclampsia. Of 29,035 with records at 35 to 36 weeks, 619 had cases of at-term preeclampsia. Risk of preeclampsia and possible benefits of timed birth were assessed in both groups.

Women were commonly White, in their early 30s, and had a normal body mass index. Smoking was reported in 10% of women, medical history of high blood pressure, type 2 diabetes, or autoimmune disease in 3%, and family history of preeclampsia in 3.9%.

The average time of delivery was 40-weeks, with spontaneous onset of labor in two-thirds of patients and cesarean deliveries in about one-fourth. In the analysis, use of risk-modeling over standard clinical screening indicated timed birth could eliminate more than half the risk of at-term preeclampsia.

“Our findings suggest that over half of the cases of at-term preeclampsia may be prevented by timed (planned) birth,” said Laura A. Magee, MD, lead study author and professor of women’s health at King’s College in London. “It is important to note that being at higher risk of at-term preeclampsia was associated with earlier spontaneous onset of labor, so women at the highest risk were already less likely to deliver close to their due date.”


Scheduled childbirth may greatly reduce preeclampsia, a leading cause of maternal death.EurekAlert. April 10, 2023. Accessed April 12, 2023.