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
5-minute read
Episode #314

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.


About the Author

Sabrina Stierwalt, PhD

Dr Sabrina Stierwalt earned a Ph.D. in Astronomy & Astrophysics from Cornell University and is now a Professor of Physics at Occidental College.

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