Of the 201 women who responded to the survey at a Midwestern hospital, 102, or 50.7 percent, used these or other unprescribed methods to try to bring on labor. Other techniques they tried included exercise, laxative use, acupuncture, masturbation and herbal supplementation.

Women who tried these techniques tended to be younger, having their first baby and pregnant beyond 39 weeks.

Most women reported that their family and friends were the most common sources of information about the potential for such methods to induce labor. Fewer than half of the women who used these methods talked about it with a doctor.

Even though most of their efforts were unlikely to cause harm, the lead researcher says clinicians should probably be aware that their patients might be trying to take labor matters into their own hands.

He also said that though the exact mechanism of labor initiation remains unknown, it appears that the process begins when certain hormones are produced by the fetus.

"So despite all of these women trying to go into labor and end their pregnancies, it winds up mostly being something moms have no control over," said Jonathan Schaffir, associate professor of obstetrics and gynecology at Ohio State University and lead author of the study.

"Obstetricians and midwives may want to offer some additional reassurance to make patients feel like they don't need to pursue these other techniques."

The study is published in the June issue of the journal Birth.

The researchers distributed questionnaires over a four-month period in 2008 to women who were still hospitalized after giving birth. Eligible respondents were women over 18 years old who had completed at least 37 weeks of pregnancy and had healthy babies that did not require intensive care.

Schaffir drew on a study he published almost a decade ago in which he collected a variety of methods that women believed might be successful at inducing labor. Ten of the 11 methods he asked women about in this current study were among those reported in the previous survey.

Methods listed in the questionnaire included walking, exercise, sexual intercourse, nipple stimulation, masturbation, use of laxatives, use of enemas, ingestion of spicy food, ingestion of herbal preparations, acupuncture and starvation.

The researchers asked the women to report which of these methods, if any, they had tried during the seven days before giving birth -- with the express purpose of trying to trigger labor.

The survey also collected general demographic data and asked the women where they learned about these methods and whether they had discussed the techniques with a doctor.

Nearly half of the women -- a total of 99 -- did not use any unprescribed methods to initiate labor.

Among the 102 who did, 87 tried walking, 46 reported engaging in sexual intercourse, 22 ate spicy food and 15 performed nipple stimulation. Some women tried more than one method.

Starvation and enemas were not used at all among these women. Four women exercised, five used a laxative, two received acupuncture, one tried masturbation and one reported taking an herbal supplement.

Schaffir does not raise these issues with his patients, but he said that patients often bring up their ideas in conversations with him. Among the theories he has heard or read about in existing literature on the subject: Sex can ripen the cervix or lead to uterine contractions. Spicy food and laxatives create intestinal activity that could give the uterus a nudge. Starvation works by making a hungry baby escape the womb in search of food.

Some research has suggested that castor oil as a laxative might indeed help labor start more quickly, but it has drawbacks, including diarrhea and the risk of dehydration for the mother, and increased potential for fetal bowel movements as well.

The one method known to produce a physiological effect related to labor is nipple stimulation, Schaffir noted. This leads to the release of the hormone oxytocin, which can cause uterine contractions.

"These contractions can be hard to control, and there's some potential downside in causing too many contractions," Schaffir said. "It's just not something I recommend because there is no established safe protocol."

The average age of the women trying unprescribed methods was 27.3 years, compared to 30.1 years of age among women who let nature take its course. The study population was mostly white (62.2 percent) or African American (22.9 percent), and no difference in whether the women tried these techniques could be attributed to their race. In general, country of origin and education levels were similar in both groups of women.

Survey respondents reported that their sources of information about trying to trigger labor came from family (41 women), friends (37), physicians (26), the Internet (11), other media (nine) or nurses (six). Forty-six of the women who used one of these methods -- fewer than half -- told their physicians that they had tried to induce labor on their own.

"Regardless of whether these techniques are harmful or indicated, I think it's good for caretakers to know that their patients are trying to do things to make their pregnancy end sooner," Schaffir said.

Schaffir conducted the research with co-authors Zaid Chaudhry, an Ohio State medical student, and Jane Fischer, a staff nurse at Ohio State's Medical Center.

Note: If no author is given, the source is cited instead.

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