Risk factor for deadly newborn infections identified

NEW YORK (Reuters Health) - In pregnancy, the time between when a woman's water breaks -- what doctor's call rupture of the membranes -- and delivery is directly associated with the risk of serious infections in newborns, independent of how long labor lasts, a new study shows.

Deadly infections (also called neonatal sepsis) affect as many as 1 percent of newborns and carry a death rate approaching 50 percent. An extended time between rupture of the membranes and delivery is a recognized risk factor for infection in mom and newborn, but whether the duration of labor influences the risk is unclear.

To clarify this point, Drs. Andreas Herbst and Karin Kallen from Lund University, Sweden studied the records of 113,568 children born at term.

The incidence of newborn infection increased progressively with increasing intervals between membrane rupture and delivery, the researchers report, ranging from 0.3 percent for an interval less than 6 hours to 1.1 percent for longer than 24 hours.

An increased time between membrane rupture and delivery was the most significant independent risk factor for infection in the newborn, conferring a 29 percent increased risk per 6-hour increase.

The duration of labor, however, was not independently associated with the risk for newborn infection, the investigators found.

In most cases, rupture of the membranes occurs after labor has already started. In some women, this happens before labor starts. Experts advise pregnant women to call their health professional immediately or go to the hospital when their water breaks.

SOURCE: Obstetrics and Gynecology September 2007.