Women were less likely to develop infections, and fewer babies were admitted to neonatal intensive care units when labor was induced than when labor was allowed to begin spontaneously after a premature water break at term, according to the review by Philippa Middleton of the University of Adelaide in Australia and colleagues.
However, the researchers found no significant differences in newborn infection rates between the two groups of women. And the numbers of Caesarean section and vaginal births assisted by forceps or a vacuum device also were similar between women whose labor was induced (planned) and women whose labor was spontaneous (expectant).
The review appears in the current issue of The Cochrane Library, a publication of The Cochrane Collaboration, an international organization that evaluates medical research. Systematic reviews draw evidence-based conclusions about medical practice after considering both the content and quality of existing medical trials on a topic.
"Since planned and expectant management may not be very different, women need to have appropriate information to make informed choices," Middleton and colleagues conclude.
Only one of the 12 studies included in the review asked women whether they preferred induction or watchful waiting. The study found that women who had their labor induced were significantly more likely to say they were satisfied with their experience.
"It is vital to have a better understanding of women's preferences regarding whether or not they wish to be immediately induced or whether they wish to wait for spontaneous labor if their membranes have ruptured prematurely at term," Middleton said.
A pregnant woman's water breaks when the placental membrane ruptures at the start of or during labor. Premature rupture of the membrane occurs before labor begins and has been associated with complications such as infection and compression of the umbilical cord. When premature rupture happens at 37 weeks, which is considered a full-term pregnancy, labor usually starts spontaneously within 24 hours but can be delayed for up to a week.
Middleton and colleagues analyzed 12 studies of nearly 7,000 women who had premature rupture of the membrane at 37 or more weeks of pregnancy. Most were enrolled in a 1996 study that included 5,042 women.
Across the studies, women who had labor induced were less likely than those who waited for labor to develop an infection of the placental membranes called chorioamnionitis. Middleton and colleagues calculated that one case of chorioamnionitis would be avoided for every 50 women undergoing induced labor.
Although newborn infection rates were similar between the induced and spontaneous labor groups, 2 percent to 3 percent of infants born under premature water break conditions will develop infections, said Brain Mercer, M.D., an expert in premature births and pregnancy complications at Case Western Reserve University and MetroHealth Medical Center in Cleveland.
"Because women undergoing expeditious delivery are more likely to undergo continuous fetal monitoring until delivery, this practice should reduce the potential for fetal death," Mercer said, acknowledging that fetal death under these conditions is a "rare but devastating outcome."
Despite similar infection rates, newborns in the Cochrane review were less likely to go into an intensive care or special care nursery after induced labor deliveries. On average, one fewer newborn was admitted to intensive care for every 20 induced labor deliveries, the reviewers found.
Babies born after premature rupture and spontaneous labor may be considered higher risk patients than those born after induced labor, making them automatic candidates for intensive or special care under hospital policies, Middleton said.
Despite the review's mixed findings, Mercer believes that women should be offered induced labor as a first option, based on the current evidence. Women who want to wait for labor should be told about the increased risks of waiting, such as the possibility of infection, he suggests.
"While no pregnant woman can be guaranteed an optimal outcome, current evidence suggests that women undergoing conservative management of [premature rupture] at term are ultimately more likely to be dissatisfied with their experience," Mercer said.
The Cochrane review was supported by the University of Adelaide and the National Health Service Programme for Research and Development, United Kingdom.
Contact Philippa Middleton at +61 8 8161 7612 or firstname.lastname@example.org
Dare MR, et al. Planned early birth versus expectant management (waiting) for prelabour rupture of membranes at term (37 weeks or more). The Cochrane Database of Systematic Reviews 2006, Issue 1.
The Cochrane Collaboration is an international nonprofit, independent organization that produces and disseminates systematic reviews of health care interventions and promotes the search for evidence in the form of clinical trials and other studies of interventions. Visit http://www.cochrane.org for more information.
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