Oxytocin does not boost prospects for normal births

Jul 15 2011

A new Cochrane review says that oxytocin, a medication often used to quicken slow-paced labor in its early stages, doesn't boost the prospects for normal births. Riskier births that required cesarean section or the use of forceps didn't become less common.

If doctors want to reduce the need for potentially dangerous emergency C-sections, "we need to develop better ways of managing slow progress because our standard treatment ─ oxytocin ─ probably does not work" in terms of preventing them, said lead review author George Bugg, a fetal medicine consultant at Queen's Medical Center in Nottingham, England.

However, the treatment doesn't appear to be harmful, at least judging from the experiences of the women included in the reviewed studies. And there was a potentially beneficial effect: oxytocin seemed to knocked an average of almost two hours off the length of the labor process.

At issue is labor that gets stalled early in the birth process, potentially endangering the health of both mother and child, Bugg said. Slow labor contributes to the necessity of about a fifth of all cesarean section procedures, he said.

That's where oxytocin ─ the synthetic hormone known as Pitocin ─ comes in. Over the past four decades, physicians have used it to speed up labor and hopefully avoid the possible risk of birth by cesarean or with the assistance of forceps.

"Oxytocin is given by an intravenous infusion and increases the frequency, strength and duration of contractions," Bugg said. "There are set infusion regimens which do not vary widely worldwide. If too much is given, it can cause extremely strong contractions, which in severe cases can cause the baby to die or the womb to rupture."

The use of oxytocin isn't universally accepted. "It's been vilified by in the lay press by those who say evil doctors are trying to force babies to come out and forcing women to accept oxytocin. There may be some perception out there that that it's harmful and may be overused," said Jonathan Schaffir, M.D, an associate professor of obstetrics and gynecology at Ohio State University College of Medicine.

Patients should note the review's message that oxytocin didn't cause any harm, Schaffir added.

The authors of the new review examined eight studies, which included 1,338 women, to determine whether the use of oxytocin posed risk to women or helped them avoid the dangers of labor that takes too long.

The review was published by The Cochrane Collaboration, an international organization that evaluates medical research. Systematic reviews like this one draw evidence-based conclusions about medical practice after considering both the content and quality of existing medical trials on a topic.

"When we compared oxytocin infusions with no treatment or its delayed use, we found it had no effect on the number of cesareans performed or operative vaginal delivery rates," Bugg said. "We did not notice any harmful effects on the mothers of babies."

The review authors couldn't judge the safety of oxytocin on the fetuses themselves. It's not clear if the drug boosts the rare risk that a fetus will die. "No bad outcomes were seen in the trials, but just over 1,000 women in total were included," said review co-author Jim Thornton, a professor of obstetrics and gynecology at the University of Nottingham. "Really bad outcomes in labor only affect about one in 1,000 labors."

So should doctors use oxytocin to speed up stalled labor? John Thorp, M.D., a professor of obstetrics gynecology and maternal child health at the University of North Carolina, said there's still plenty that is unknown about the birth process, making it difficult to generalize. "We need a better understanding of normal and abnormal labor: how to measure it, how to describe it and what are the biological phenomenon underlying it."

Once physicians develop more knowledge, he said, they'll better be able to figure out which women need a boost from oxytocin.

For now, study co-author Bugg said, oxytocin "can be used to speed up the second stage of labor, and may have benefits. It clearly has benefits in being given in the third stage in order to reduce the risk of postpartum hemorrhage."