Postterm delivery raises childhood epilepsy risk

By Will Boggs, MD

NEW YORK (Reuters Health) - Infants who are born after 42 weeks of pregnancy or later have an increased risk of developing epilepsy in the first year of life, according to a report in the specialty journal Pediatrics.

These findings add to the growing evidence that prolonged pregnancies are associated with a higher rate of adverse effects, Vera Ehrenstein told Reuters Health. "Thus, prevention of postterm delivery itself, by providing timely prenatal care, is the most important intervention."

Ehrenstein, from the Boston University School of Public Health, and her colleagues examined the association between postterm delivery and the risk of epilepsy during the first 12 years of life among more than 277,000 children born in three counties of Denmark.

Of the 2,805 cases of epilepsy that were documented, 23 percent occurred during the first year of life, the results indicate.

The number of children with epilepsy in the first year of life correlated with the length of pregnancy, the investigators found. Compared with infants born between 39 and 41 weeks, epilepsy increased by 30 percent for children delivered at 42 weeks and doubled for those born at 43 weeks or later.

The magnitude of this effect "varied according to delivery mode," the team found. For example, for births at 43 weeks or later, the epilepsy cases increased by 30 percent among infants born by unassisted vaginal delivery; an increase of nearly three-fold was associated with instrument-assisted birth; and the rate rose by almost five-fold in infants delivered by cesarean section.

However, the investigators found no association between prolonged pregnancy and the risk of developing epilepsy later than the first year of life.

"This is the first study examining the association between postterm delivery and childhood epilepsy," Ehrenstein said. "Because both conditions are rare, a nationwide study in Denmark would be important to confirm these findings."

In addition, Ehrenstein said, "it would be essential to know how the association between postterm delivery and epilepsy behaves under different obstetric conditions: planned vs. emergency cesarean delivery; or induced vs. spontaneous labor. We hope to be able to address these questions in future studies."

SOURCE: Pediatrics, March 2007.