Does Anything Actually Make You Go Into Labor?

Most of the popular legends are more myth than fact, but there are a couple of interesting exceptions.

Credit...Beth Hoeckel

This story was originally published on May 6, 2019 in NYT Parenting.

I don’t remember much about my two pregnancies, but I do recall that the last few weeks felt like years. I was huge and everything ached, and I was desperate to meet my babies.

So I tried to induce labor myself. I got acupuncture for the first time in my life. I walked — OK, waddled — in circles around my basement watching “Law & Order” reruns. I poured Tabasco sauce on everything. I even saw a chiropractor, who said she could put me into labor with a few minor adjustments. She didn’t, but at least my back felt better — for about 20 minutes.

According to a 2013 survey of 2,400 mothers in the United States who gave birth between 2011 and 2012, nearly 30 percent tried to induce labor on their own. And their reasons for doing so, my reporting suggested, are various. They’re tired of being pregnant or want to avoid medical inductions or C-sections, for example; or perhaps they simply want to deliver on a particular day. (A note of caution: Doctors do not recommend trying to self-induce labor before 39 weeks, because the fetus’s brain is still developing.)

[The topics parents are talking about. Sign up now to get NYT Parenting in your inbox every week.]

Although nothing I tried worked, I have since wondered: Do any of these old wives’ tales have merit? To find out, I spoke with three obstetricians, including one who has studied the issue, and dug into the scientific literature. Unfortunately, most of the popular legends are more myth than fact, but there are a couple of interesting exceptions.

Walking is the most popular approach women take to self-induce labor — at least that’s according to one of the most recent studies on the topic, published in 2011 in the journal Birth. I certainly thought it was worth trying. The idea is that walking might “encourage gravity to bring the baby lower into the pelvis,” explained Dr. Jonathan Schaffir, an obstetrician-gynecologist at the Ohio State University Wexner Medical Center and a co-author on the study. This, he said, might ultimately “shake the baby out of its nest.”

Yet no research suggests that walking actually does this — because no such studies have been done. Researchers have never conducted a trial, for example, in which some at-term pregnant women walk and others don’t, and compare what happens to whom and when. That said, many mothers believe that walking incited their labor. In a study published in The Journal of Perinatal Education in 2014, researchers interviewed 663 women after they had gone into labor without a medical induction and given birth. About 30 percent of them said that they thought that walking had done the trick. But it’s impossible to know whether walking truly had an effect or whether these women just happened to be walking before they went into labor. “There is definitely a benefit to having patients be able to move around when they’re in labor,” said Dr. Anna Burgansky, director of obstetrics and gynecology at NewYork-Presbyterian Lawrence Hospital in Bronxville, who added that walking can help with labor progression and pain. “But there is really no data that walking before labor does anything.”

In addition to my heavy Tabasco use, I also recall eating many Thai curries late in my pregnancies, hoping they might speed labor along. The rationale goes something like this: Spicy food irritates the gut and causes it to move its contents more quickly than it would normally, so it might also initiate uterine contractions.

But only one study, published in 2015, has evaluated this claim, and it’s difficult to interpret. In it, researchers asked women who had been admitted to the hospital for preterm labor, or whose water had broken early, what they had been doing in the 24 hours prior. The researchers then compared those answers to answers they got from similar pregnant women who hadn’t gone into preterm labor. They found that women who said they had recently eaten spicy food had seven times higher odds of going into preterm labor or having their water break early than those who didn’t. But from this data, it’s impossible to know whether eating spicy food will also induce labor in women at term. And the experts I spoke with weren’t hopeful. “I think all it will do is give you heartburn,” said Dr. Judette Louis, an OB-GYN at the University of South Florida School of Medicine and a spokeswoman for the Society for Maternal-Fetal Medicine.

There are plausible reasons to think that sex might start labor. First, “semen contains compounds called prostaglandins, which are similar in structure to what [doctors] use as medical interventions to start labor,” Dr. Schaffir explained. These compounds help to soften and open the cervix, which happens in early labor. Female orgasms can also cause uterine contractions, another crucial labor component.

Yet little research has investigated whether sex actually induces labor, and the research that has been done has been based on a small number of women and has had discouraging results. In a 2006 study, Dr. Schaffir asked 93 pregnant women who were 37 weeks along to report how frequently they had sex from that point on until they delivered. His findings, which were published in the journal Obstetrics & Gynecology, suggested that women who had any sex at all went into labor later than those who didn’t. Then, in 2007, researchers in Malaysia conducted a clinical trial in which they told 108 pregnant women, all 37 weeks along, to have sex “as frequently as possible”; they did not give sex-related advice to a second group of 102 pregnant women. Although the women in the first group did have more sex than those in the second, they did not go into labor any earlier.

[Read our guide on when sex is safe during a pregnancy, and what to expect of your sex life while pregnant.]

These disappointing results may stem from problems of dose. The concentration of prostaglandins in semen may be too low to affect the cervix, Dr. Schaffir said. And while female orgasms can spark contractions, a few contractions are not enough to initiate labor. Alternatively, Dr. Schaffir said, there may be no relationship between sex and labor at all. But unless your doctor tells you otherwise, “there’s nothing wrong with having sex if you want it,” Dr. Louis said.

One sex-related intervention may induce labor, according to some studies: Nipple stimulation, which involves rolling a nipple between your fingers, using a breast pump or placing a warm compress on your breast, in some combination, for up to three hours a day. In a 2005 Cochrane systematic review — more recent studies have not been done — researchers analyzed results from six clinical trials with a total of 719 women who were at least 37 weeks along. They found that those whose nipples had been stimulated — typically for between one and three hours a day, one nipple at a time — were 33 percent more likely to go into labor within the next 72 hours than women whose nipples were left alone. Nipple stimulation also reduced the risk of heavy bleeding after delivery by 84 percent.

When a woman’s nipples are stimulated, her body releases the hormone oxytocin. “Physicians use a synthetic form of oxytocin [to induce] labor, so it makes sense that it would work,” Dr. Schaffir said. But he also cautioned that there has not been enough research to show that nipple stimulation is safe and effective to do at home. “The reaction to nipple stimulation is very unpredictable,” he explained. “Sometimes the contractions can be so strong that they cut off blood flow to the uterus,” which could pose risks to the fetus. So if you’re going to try stimulating your nipples to induce labor, only do so under a doctor’s supervision.

I was so hopeful that acupuncture — which involves inserting fine needles into specific points of the body — would push me into labor. But if I’d taken a close look at the evidence, I probably would have been skeptical. No trials have found that acupuncture or acupressure (using thumbs or fingers to apply pressure to specific points) initiate labor faster; in fact, a handful of trials have found that women who receive acupressure or acupuncture late in their third trimesters do not give birth any sooner than women who don’t. Two studies do suggest that acupuncture can soften the cervix, but “these studies don’t provide enough information to recommend [acupuncture or acupressure], and they suggest larger and better-done studies need to be carried out,” Dr. Schaffir said.

Castor oil (an oil made from castor beans) is a folk remedy that some studies do seem to suggest prompts labor, but only among women who have previously given birth. In a small 2018 trial conducted in Israel, 38 pregnant women between 40 and 42 weeks along were given about 2 ounces of castor oil to drink, while a second group of 43 pregnant women at the same stage were given about 2 ounces of sunflower oil. Although there were no overall differences in terms of who went into labor when, the researchers found that of the women who had previously given birth, those who drank the castor oil went into labor faster than those who drank the sunflower oil: Within 48 hours, 65 percent of the castor oil drinkers had gone into labor, while only 35 percent of the sunflower oil drinkers had. But the study was small and needs to be replicated. Dr. Burgansky warned, too, that castor oil does have downsides: It is a laxative, it can make some women nauseated and it doesn’t taste very good. So sip at your own risk.

Melinda Wenner Moyer is a mom of two and a science journalist who writes for Slate, Mother Jones, Scientific American and O, The Oprah Magazine, among other publications.