Birth prep

Inducing Labor—What Does The Latest Research Say?

Inducing labor is increasingly common these days, but it wasn’t always this way. Not too long ago, doctors were hesitant to intervene until quite late in pregnancy. Today, you’ll find the internet is full of tips for inducing labor naturally, but are they effective? (And more importantly—are they safe?)

Here, we’ll give the full scoop on what the latest research says about inducing labor, what it means for you, and what you can expect if you learn you’ll need to be induced.

Key Takeaways:

  • It’s usually best to go into labor on your own. (But in some cases—such as when the baby is in distress—this is just not possible.)
  • If your doctor is concerned about your level of amniotic fluid, make sure to stay well hydrated and ask for what’s called a “deep vertical pocket” test.
  • Of the “natural” methods for inducing labor, the most effective is nipple stimulation and what’s known as “sweeping the membranes,” a procedure your doctor can perform during a cervical exam.


What does it mean to induce labor?


Before we go lumping all inductions into the same bucket, it’s helpful to know that there are two different types of inductions: those that are recommended for a medical reason (like when your doctor suspects that the baby is in distress) and those that are not. Inductions that are not executed for a medical reason are called elective inductions. This type of induction has become increasingly common in recent years. (And while you’re getting prepped for labor, check out our post on the stages of labor.)

How are inductions performed?


There are two different ways that inductions are performed:

  • If your cervix has already begun to soften and dilate, your doctor will likely give you a drug called Pitocin to start contractions. Pitocin is a synthetic version of oxytocin, which is a naturally occurring hormone in the body that helps your uterus contract during labor.


  • If your cervix has not begun to soften and dilate, your doctor may give you the Pitocin drug as well as either a prostaglandin drug like Misoprostal—which will soften the cervix—or something called a balloon catheter to stretch out the cervix.

Why are inductions so much more common today?


In 1990, only 10% of births were medically induced. But by 2010 that percentage had ballooned to 23.8%. Why the sharp increase? One factor is medical malpractice lawsuits. Another is that obstetrics has become much more consumer-driven, so some women request inductions simply for the scheduling convenience. But in recent years, organizations like the March of Dimes and the American College of Obstetricians and Gynecologists have been pushing to reduce the rate of early elective deliveries.


What are the guidelines?

The American College of Obstetricians and Gynecologists now recommends that induction is used before 41 weeks only when medically necessary—for example, when a mother develops hypertension or her water breaks, but labor does not begin.


What is the problem with inductions?


It’s been pretty widely believed for a while that inductions increase the cesarean section rate. But some researchers weren’t so sure about the veracity of that assumption, because it was based on older medical research. So in 2018, these researchers organized a study of more than 6,000 women at the National Institute of Child Health and Human Development to test the theory.

Surprisingly, that study found that the cesarean section rate actually went down among women who were induced. (The rate fell from 22% among women who weren’t induced to 19% among women who were.) This study also found that there was no major increase in complications among women who were induced. This study counters the long-held belief that induction increases the cesarean section rate. Even though this 3% change is relatively small, the study’s author Dr. William Grobman pointed out that reducing the overall cesarean section rate is extremely important, so even a small percentage drop is significant and benefits women’s health overall.

Another study also found that being induced at 41 weeks or more resulted in slightly better outcomes (fewer perinatal deaths and cesarean sections) but pointed out that the absolute risk for perinatal mortality was small. But some organizations (like as the March of Dimes, for example) are skeptical of these results and caution that women should still evaluate the overall pros and cons of induction.

The takeaway? Whether or not to be induced is not a black-and-white decision. It’s more like a grey zone that depends on your specific case, and you should talk to your doctor.


When are inductions necessary?


If you’re worried about the possibility of getting induced—and hoping to avoid it—there are a few situations in which it may be necessary for the sake of your health and that of your baby. But it’s important to be aware of the latest research and, when necessary, to self-advocate.  Here are the cases in which your doctor may suggest an induction, whether or not it’s in your birth plan:


  • If you’re past your due date, there are some risks that your placenta may begin not to function optimally, which means that your baby may not be getting enough oxygen and nutrients. The risk of stillbirth also increases at this point.


  • If your water breaks before contractions begin.


  • If you’re having any complications like gestational diabetes, hypertension or preeclampsia.


  • If your amniotic fluid is low, or the baby otherwise seems not to be tolerating pregnancy well, which can be assessed from what’s called a “nonstress test” that your doctor may ask you to take.


The takeaway? While it’s best to deliver on your own in most cases, there are some situations in which induction is the better call. Your doctor will talk to you about your specific situation and will run some tests to see how your baby is doing.


How do you induce labor naturally?


According to everything from a Wikipedia entry to folklore from centuries ago, there are supposedly natural ways to encourage your baby to come out—acupuncture, sex, walking for miles, or inhaling teas and tinctures. But you should look at each of these suggestions with a skeptical eye. (Most of them have little to no supporting scientific evidence.)

Here are some of the suggestions you’ll find on the internet. And according to this study, here’s what the research says about the effectiveness and safety of each method.

  • Castor and primrose oil—Not only are these oils not effective in starting labor, but they may actually increase the likelihood of complications.


  • Sex—This one actually is based in science, as semen contains something called “prostaglandins” that soften and ripen the cervix. But this study found that the role of sex in starting labor is uncertain.


  • Breast stimulation—There is some evidence to support that this method is effective (and it is clearly safe). Specifically, this study found that breast stimulation for 3 days (15 minutes per session for a total of one hour per day) was effective.


  • Red Rasberry tea—This is an old (mid)wive’s tale. It’s been suggested over the years based on traditional knowledge, not scientific research—which merely suggests that it may be beneficial, but the jury is still out.


  • Acupuncture—Clinical research is mixed. Some studies (such as this one) have shown that it may be beneficial while others have shown that has no effect.


  • Blue cohosh—This is plant root was used traditionally by Native Americans to induce labor. But it can be harmful and should not be used in pregnancy—as it may cause defects in the baby or toxicity in the mother.


  • Stripping the membranes—(Warning: this is not something you can do by yourself!) During a cervical exam, your doctor can detach the bag of water from your uterus. It usually works, and women who have their membranes stripped are 25% more likely to go into labor.


What are the risks of inducing labor?


Research has shown that elective induction (induction without an apparent medical reason) before 39 weeks increases risks for babies including:

  • Breathing problems
  • Infections
  • Being admitted into the NICU (Neonatal Intensive Care Unit)


How do I know if my baby is tolerating pregnancy O.K.?


There are two main tests that doctors use to see how well the baby is faring: a nonstress test (otherwise known as a cardiotocograph or CTG) and measuring amniotic fluid levels. But the reality is, research has shown that these tests have some limitations. According to this study, there is considerable variability in how the nonstress test is read—making false negatives ( as well as false positives) possible.

In the nonstress test, (NST) you’ll be hooked up to a fetal monitor for about 20 minutes. Your doctor will be looking to see if the baby is moving around as he should be, as evidenced by variations in his heart rate. However, if the baby is asleep, his heart rate will be consistent and won’t be accelerating the way it would if he were awake. In order to make sure that your baby is awake, your doctor may clap or have you drink sugar right before your test. But there is no scientific evidence to justify that using juice in this instance is effective.

Something known as a biophysical profile (BPP) offers a more complete picture of how your baby is doing, as it includes a nonstress test in combination with ultrasound. The ultrasound will check for:

  • Fetal breathing
  • Fetal movements
  • Fetal tone
  • Amniotic fluid volume


How do I know if I have enough amniotic fluid?


Low amniotic fluid, a condition called “oligohydramnios” is a real and serious concern. If there’s not enough fluid, the umbilical cord can become compressed, cutting off nutrients and oxygen to your baby.

Research has shown that babies of mothers with low fluid volume have higher mortality rates and are more likely to spend time in the NICU. So if your fluid is low, your doctor will want to run some other tests (such as the nonstress test) to learn more about how the baby is doing. And if the results of that test show that the baby is under stress, then induction is recommended.

But, a low fluid reading on its own (something called “isolated oligohydramnios”) is not necessarily a problem, as long as the baby is doing well otherwise. Though it is common for inductions to happen in this case, there is little evidence that justifies being induced in this case. In fact, research has shown that when low amniotic fluid is not accompanied by other indications of fetal distress, the babies do just as well when left alone to come out in their own time.

There are also a couple different ways to measure amniotic fluid:


  • One is by measuring the total fluid volume (or AFI).


  • Another is by measuring what’s called the “deepest vertical pocket.”


Imagine your uterus is a lake, with some deep sections and some shallow sections. The AFI measures the total amount of water in the lake, while the deepest vertical pocket measures the deepest section, which is really the only one that matters. So the deepest vertical pocket test will still tell you if there’s a problem, but it is more likely to exclude those situations in which there is no reason for concern.

Research has also shown a pretty simple (and obvious) intervention for low fluid—drinking water!  This study found that when women drank two liters of water before their ultrasound, their amniotic fluid level increased.


Aarthi Gobinath, PhD

Aarthi Gobinath earned her PhD in neuroscience from the University of British Columbia. Her research covers the ways that stress affects the male and female brain differently.

She tackled the issue of sex bias in research by looking at why standard treatments for depression don't always work in the case of postpartum depression. Her work has been covered by Vice and Massive Science.

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