Until recently it was an axiom in obstetrics that doctors needed to deliver a baby within 24 hours after a woman's water broke to prevent infection or other serious complications. But a new multinational study of more than 5,000 women by Canadian researchers has found that the increasingly popular practice of "expectant management" -- waiting up to four days for labor to begin naturally -- may not be riskier than using drugs to induce labor.

Researchers at the University of Toronto, who studied 5,041 women who gave birth at 72 hospitals in Canada, the United Kingdom, Israel, Sweden and Denmark, found few differences in infection or other complications between women whose labor was induced with either of two drugs and those whose conditions were monitored for up to four days, a practice dubbed "expectant management." Women in the latter group were induced if a complication developed or if labor had not occurred within four days after their water broke.

In about 8 percent of full-term pregnancies, fetal membranes rupture, releasing a gush of amniotic fluid, but labor does not begin. Inducing labor by administering contraction-stimulating drugs -- typically the hormone oxytocin -- has been standard procedure. Yet in a significant number of cases, labor does not progress and a Caesarean delivery is required.