After 40 weeks of pregnancy, your belly heavy and your back aching, you might be looking for just about any natural trick to induce labor — and in your research, you probably came across castor oil. Indeed, for thousands of years women have turned to this thick, yucky-tasting tradition in the hopes of hastening baby’s arrival. Made from the seeds of the plant Ricinus communis, castor oil is a folklore method to encourage labor. While research shows that it can, in fact, bring on contractions, it also has a host of side effects, ranging from icky (diarrhea) to potentially dangerous (dehydration). So if you’re deciding whether to gulp this unpleasant tonic, it’s essential to carefully weigh the pros and cons — and, of course, consult your health care provider first.

Does it work?

Castor oil is better known as a laxative than a labor-inducer — and it turns out that the two aren’t unrelated. Scientists have shown in research on mice that the active compound in castor oil attaches to the molecules that makes muscles — in both the intestines and uterus — contract. And if you’re pregnant, forcing the uterine muscles to contract might help jumpstart labor. In multiple studies of women at term, more than half of those who took a dose of castor oil went into labor within 24 hours — that’s compared to only 4 percent of those who didn’t glug it at all. But that doesn’t necessarily mean castor oil will induce labor for you: Almost half the women who received castor oil didn’t go into labor immediately.

What are the risks?

Unfortunately there’s no way to target castor oil so it induces labor without affecting the intestines. That means taking a dose can lead to some real tummy turmoil: diarrhea, an upset stomach and cramping. In fact in a 2013 study, every single woman who took a dose of castor oil to induce labor felt nauseated afterward. Since diarrhea and vomiting can lead to dehydration, it’s important to be ready to drink lots of water to replace that lost fluid. But even if you stay on top of your water intake, the stress of severe cramping can be dangerous for your baby, potentially making his heart rate increase — and making you feel even more uncomfortable than you already were.

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Some anecdotal evidence also suggests that since castor oil passes through the placenta to your baby, it can make baby, in turn, pass his first stool, called meconium, before he’s born. And that can potentially cause problems after birth. But other research, including a 2009 study looking at more than 600 pregnant women in Thailand, found no difference in the timing of meconium or the health of a newborn — or, for that matter, the time to birth — after a mom took castor oil.

The other potential risk of castor oil is that is can cause irregular, painful contractions. While any contractions at all may seem like a good thing, hours of irregular contractions — which aren’t real labor and don’t get you any closer to snuggling your baby — can be exhausting. One of the most common side effects of castor oil, in fact, (after diarrhea and nausea) is exhaustion, which can make labor trickier when it does finally arrive.

Should you try it?

Like any other medical intervention in pregnancy, ask your healthcare provider first before trying castor oil. Depending on your health and any risk factors associated with your pregnancy, she may have unique reasons for you to forgo it.

If you do get the OK to try castor oil after you've passed your due date, follow your practitioner’s dosing recommendations. In most studies where labor was successfully induced, women received 60 mL (about 4 tablespoons) of the tonic, often mixed with orange juice to mask the taste. It’s probably best to take in the morning, so you can monitor your symptoms, drink plenty of water, and won’t be kept awake in the bathroom all night. And if the first dose doesn’t do it, don’t overdo it with another. It just means you’ll need to stay patient: Your baby will arrive eventually in his or her own sweet time.

Is it OK to use castor oil as a laxative during pregnancy?

If you're constipated during pregnancy and are hoping castor oil can help get things moving, don't try it (or any other laxative, for that matter) before your due date without your doctor's OK. You're better off avoiding the chance you unintentionally induce labor as well (you want to give your baby the best odds to be full-term when he is born, after all!).