Although acupuncture is promoted as a way to induce labor in women who go past their due date, a new study adds to evidence doubting its usefulness.

Researchers found that among 125 pregnant women who were past their due dates, those who were randomly assigned to undergo two acupuncture sessions were no more likely to go into labor over the next 24 hours.

Of those women, 12 percent went into labor, versus 14 percent of those who were randomly assigned to have a “sham” version of acupuncture.

The findings, reported in the obstetrics journal BJOG, add to evidence that acupuncture may not be an effective way to induce labor in “post- term” pregnancies - those that go beyond 41 weeks.

About 5 percent to 10 percent of pregnant women have a post-term pregnancy, a delay that raises the risk of complications during labor. Because of this, doctors routinely induce labor when a pregnancy lasts beyond 41 weeks.

During standard labor induction, a doctor uses instruments to rupture the amniotic sac or stretch the cervix, or gives synthetic forms of prostaglandins or oxytocin - hormones that normally help trigger labor. Acupuncture has been promoted as an alternative; in theory, it may work by stimulating the nervous system, which in turn could cause the uterus to contract.

And there is a need for alternatives in labor induction, said Dr. Niels Uldbjerg, a professor of obstetrics and gynecology at Aarhus University Hospital in Denmark and the senior researcher on the new study.

Many women prefer to avoid medications during pregnancy and labor, and all of the standard forms of labor induction raise a woman’s odds of ultimately needing a C-section or instrument-assisted delivery, Uldbjerg noted.

However, several clinical trials in the past few years have found no benefit of acupuncture for labor induction. These latest findings add to that evidence.

“This study clearly demonstrates that acupuncture is not an alternative to (standard) methods” of labor induction, Uldbjerg told Reuters Health in an email.

Acupuncture has been used for more than 2,000 years in Chinese medicine to treat a wide variety of ailments. According to traditional medicine, specific acupuncture points on the skin are connected to internal pathways that conduct energy, or qi (“chee”), and stimulating these points with a fine needle promotes the healthy flow of qi.

For their study, Uldbjerg and his colleagues randomly assigned 125 women with post-term pregnancies to either have “true” acupuncture - with needles inserted at sites that, according to traditional medicine, are associated with uterine contractions and labor - or a “sham” version of the same, using blunted needles that did not pierce the skin. Each woman received two sessions in one day.

Overall, the study found no difference between the two groups in the percentage of women who went into labor within 24 hours. Nor were there differences in other outcomes that the researchers assessed - such as dilation of the cervix or, in women who went into labor, the length of time it took them to deliver.

“The results are very clear,” Uldbjerg said. “Acupuncture as used in this trial does not induce labor in post-term pregnant women.”

He and his colleagues do acknowledge, however, that a “more intensive” course of acupuncture could arguably have produced different results. They also note that many acupuncturists say that to achieve an “optimal effect,” the therapy must be individualized from person to person.

Post-term pregnancy is one of the major reasons that women have a labor induction. But inductions may also be done under circumstances where the fetus is in danger of not getting enough nutrients or oxygen from the placenta; when a woman’s “water breaks” before labor and labor does not spontaneously begin soon after; or in some cases in which the mother has a medical condition - like gestational diabetes or high blood pressure - that is putting her health or her baby’s health at risk.

According to Uldbjerg, acupuncture has been studied as a way to induce labor in cases where a woman’s water breaks early, and the results have been “inconclusive, but mostly negative.” Whether acupuncture could be helpful in other circumstances is unknown.

A growing number of studies in recent years have investigated acupuncture for a wide range of health problems, with some showing benefits for conditions like chronic back pain and migraines.

Its possible usefulness during childbirth is also receiving more attention, though study results are so far mixed.

A few studies, for example, have suggested that acupuncture can help control pain during labor. However, a recent review of 10 clinical trials found overall there is no strong evidence that acupuncture effectively quells labor pain.

SOURCE:  BJOG, online June 24, 2010.