The Science (or Lack Thereof) Behind Inducing Labor Naturally
We have centuries of lore and rumor on how to get the process of labor started naturally. But do any of them actually work?
Sabrina Stierwalt, PhD
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The Science (or Lack Thereof) Behind Inducing Labor Naturally
Despite the age-old practice of giving birth, we still understand surprisingly little about how the process of labor actually gets started. We know the hormones like oxytocin that are involved and we have a clear understanding of how the cervix changes as it prepares for labor and delivery. But how does it all start? Why are some babies eager to come out ahead of schedule while others prefer to stay put until the last possible moment? How does the baby signal to the mother’s body that it’s go time?
We may not have the answers to these questions yet, but we do have centuries of lore and rumor on how to get the process started naturally. The bakery in my neighborhood guarantees eating two of their lemon cupcakes will put you into labor and many believe strongly in the famous ‘maternity salad’ sought by celebrities at a Californian café. Plus, pregnancy can be physically exhausting and is often uncomfortable, so many women are willing to try just about anything to move on to the next stage. But do any of them actually work?
Let’s take a look at the scientific evidence (or lack thereof) behind a few of the most popular methods for inducing labor outside of the hospital.
Spicy Food
Some women swear by the power of spicy food to induce labor naturally. One theory suggests that triggering activity in your stomach or bowels through spicy food can also then irritate your uterus since they are all in close quarters by the end of pregnancy. But before you head for the Thai place on the corner or start smothering your food in Cholula, there is no clinical evidence that adding the spice actually leads to labor with any reliability. You may just end up with heartburn instead.
Castor Oil
Drinking a few tablespoons of thick, gooey castor oil, the oil extracted from castor beans, is often credited with bringing on labor naturally, again by irritating the bowels and the GI tract. Most tests of the efficacy of castor oil in starting labor fail to see any clear links, although there are some.
For example, in a literature-based study of less than 60 women, researchers found taking castor oil did increase a woman’s chance of going into labor within 24 hours. However, it’s important to note that all of the women in that study were at 40+ weeks pregnant—in other words, already past their due date.
However, castor oil is a laxative and thus has significant side effects like GI upset and diarrhea. Some doctors further warn that any contractions brought on by castor oil could be stronger than the ones you’d have normally. Since uterine contractions slow the flow of oxygen to the baby, stronger contractions could mean the baby gets less oxygen than it needs.
Pineapple
The core of a fresh pineapple contains an enzyme known as bromelain which works to break down proteins in tissue. Bromelain is actually used as a meat tenderizer and is why your mouth might tingle when you eat pineapple. Rumor says the enzyme can break down tissue in the cervix but unfortunately, there’s no evidence to back that up. The bromelain is not fully absorbed by your body to start and your stomach is already very acidic, meaning there’s a lot of competition.
Acupuncture
Acupuncture, or the ancient Chinese process of pricking skin or tissue with needles, has been used for centuries to get labor started, particularly throughout Asia. In a study of 364 women in Adelaide, Australia, doctors prescribed two sessions of manual acupuncture in the two days leading up to their scheduled inductions. They found no difference between the acupuncture recipients and the control group (those that did not receive acupuncture) as far as any reduction in the need for medical inductions or in the duration of labor.
In a much smaller study of 56 women that were within a week of their due date and had not previously given birth, 70% of the group that got acupuncture ended up going into labor naturally while only 50% of the control group did. The C-section rate in the group receiving acupuncture was also nearly 50% lower, although the lower rate could be a reflection of the lower need for medicated induction.
Going for a Walk
Many women get back to basics when it comes to trying to induce labor naturally: good old gravity. Going for a walk means a mom-to-be is upright and swaying her hips, which could help move the baby downward, and some hope this pressure on the pelvis will inspire the cervix to prepare for labor. In a study of over 600 women about their self-reported triggers for natural labor, 32% credited exercise like walking.
However, despite the popularity of this natural method of induction, the evidence that it actually works remains mostly anecdotal. If you’re considering going for a walk to start labor, keep in mind that labor is likely to be very physically taxing so you don’t want to start already exhausted.
Sexual Intercourse
Unless you are required to take some kind of pelvic bed rest, doctors and midwives often advise that you can try rounding out your pregnancy the same way you may have started it: with heterosexual intercourse. The link here also makes sense: semen contains prostaglandins, a hormone that can stimulate and soften the cervix and possibly lead to uterine contractions. These hormone-like prostaglandins are also similar to the medications hospitals use to induce labor. However, research has not been able to draw a conclusive link between sexual activity and kickstarting labor so it may be worth a try, but don’t get your hopes up.
Herbal Supplements
While many of the labor-inducing methods we’ve covered so far fall into the category of “it’s worth a shot,” the evidence is far bleaker for the use of herbal supplements. Herbs and tinctures like black cohosh, raspberry leaf tea, and evening primrose oil have all been touted for their powers to bring on labor.
However, in all cases, there is again a lack of clinical evidence showing any clear link. Even worse, studies have found that some of the herbs can have harmful effects. Cohosh, for example, has been linked to fetal heart failure and stroke, as well as maternal complications with intimidating names like severe hyponatremia, during labor.
When it comes to the scientific evidence, the jury is still out on most methods rumored to induce labor naturally. And what most of these studies tell us is that if you’re close to your due date, the chances of going into labor on your own are, by definition, already pretty high. But after waiting nine long months, it’s understandable to be impatient or overeager or just plain done with the inconveniences of being pregnant. So if you’re thinking of trying one of the methods above, or, say, the weird tea your aunt swears by, ask your doctor or midwife first.
Until next time, this is Sabrina Stierwalt with Ask Science’s Quick and Dirty Tips for helping you make sense of science. You can become a fan of Ask Science on Facebook or follow me on Twitter, where I’m @QDTeinstein. If you have a question that you’d like to see on a future episode, send me an email at everydayeinstein@quickanddirtytips.comcreate new email.
Image courtesy of shutterstock
