What Is a Foley Balloon or Bulb Induction, and What Happens During One?

If you’ve heard about using a Foley bulb or balloon to induce labor, you’re probably curious about what this device is and how it works.

Here’s what you need to know about how this induction procedure is done, along with its risks and benefits.

A Foley bulb, also known as a Foley balloon or Foley catheter, is a thin, flexible tube with a tiny balloon at the end. Your doctor may use this device to help “ripen” your cervix, which means softening and opening it.

While this might sound intimidating, it’s a common and effective method for inducing labor. Doctors typically recommend induction if you’re more than 40 weeks pregnant (i.e., you have a late-term pregnancy) or if certain complications make it safer for you to deliver your baby early.

How do Foley bulbs work?

Foley bulbs are mechanical devices that doctors usually use without any accompanying medication.

An OB/GYN can use a Foley bulb to induce labor by inserting it into the uterus and gently inflating it. This puts pressure on the cervix and encourages it to open. Labor normally starts 12 to 24 hours after the procedure. 1

What’s the difference between a Foley bulb and a Cook catheter?

There’s a similar device that uses two balloons called a Cook catheter. Regardless of whether the catheter is single-ballooned or double-ballooned, your doctor will insert it into your uterus in the same way, through your cervix.

Studies have shown that both are effective for cervical ripening. However, some suggest that Foley bulbs may lead to quicker delivery. The single-balloon method is also more common, which makes Foley bulbs cheaper and more readily available in hospitals. 2 3

Again, your doctor may recommend inducing labor if you’re overdue, meaning you’re more than 40 weeks along in your pregnancy and haven’t given birth yet. Late-term pregnancies are relatively common and aren’t necessarily dangerous, but doctors still often prefer to help get things moving rather than let them drag on.

You also may need to be induced if: 4

• You have a pregnancy complication: Pregnancy complications that put you or your baby’s health at risk, such as gestational diabetes or preeclampsia (a dangerous complication characterized by high blood pressure and swelling), warrant labor induction.
• Your baby has a problem: Your doctor may induce labor if your baby has a health issue that requires treatment, such as poor growth.
• You’re carrying multiples: If you’re carrying twins or multiples, you’ll need to go into labor sooner than with a singleton pregnancy. If labor doesn’t naturally start early, your doctor will induce it. 5

Evaluating your cervix for induction

Your doctor may use something called the Bishop scoring system to evaluate how ready your cervix is for labor. If you score at least eight out of thirteen, meaning that most signs suggest you’re ready to give birth, they’ll probably move forward with an induction.

You can expect a discussion about the method your doctor thinks is best. In addition to Foley bulbs, it’s also possible to induce labor with certain drugs and other mechanical tools, something we’ll cover in more detail further down in this article. 6

Your doctor will go over your medical history to make sure there aren’t any reasons to avoid induction. 6 7

Typically, they’ll look for signs that a vaginal birth (whether induced or natural) might be unsafe. If they see any, they should probably recommend a C-section instead.

Contraindications for labor induction include:

• Breech position: Your doctor will probably perform a C-section if your baby’s not in an ideal position for birth. For example, she could be positioned feet or bottom-first in the uterus (breech), which happens in 4% of pregnancies. 8
• Placenta previa: If your placenta is positioned too low in your uterus, a condition known as placenta previa, it can block off the birth canal and make it unsafe or impossible for your baby to pass through. 9
• Previous C-sections: If you’ve had a “vertical” C-section before, it can increase your chances of rupturing your uterus during labor. This complicates your ability to have a safe vaginal delivery. 10 The same goes for any other surgeries you’ve had on your uterus in the past, such as a myomectomy that interrupted the full thickness of your uterine wall.
• Active herpes infection: If you’re dealing with genital herpes, you could pass the disease to your baby during childbirth. This is known as birth-acquired herpes. 11

Again, if you have any of those complications, labor induction via a Foley bulb (or any other tool) will probably be off the table, and your doctor will recommend a C-section instead.

Here’s the general outline of the procedure: 7 12

Before the procedure

Your doctor will talk to you about why you’ll need the catheter and wait for your consent to proceed. They may give you a leaflet to read so that you understand the procedure’s potential risks and benefits.

They’ll also check to make sure there are no contraindications and ensure that your baby is well-positioned for delivery, usually with a quick ultrasound.

Afterward, they may ask you to lie on an exam table with your feet in stirrups, similar to a pelvic exam. Once you’re settled, they’ll examine your cervix and clean your vaginal and perineal area (the skin between your anus and vulva) with an antiseptic solution.

During the procedure

Your doctor will gently insert the Foley bulb through your cervix and into your uterus, probably with their fingers. However, if you’re not dilated enough, they might need to widen the opening with a speculum (like during a Pap smear) and insert the catheter with a pair of ringed forceps. 13

Once it’s in place, your doctor will tape the catheter to your inner thigh or tuck it into your vagina and secure it in place with gauze.

They’ll then carefully start inflating the balloon with air or about 1 ounce (30 ml) of sterile water or saline.

As the balloon expands, it’ll gently put pressure on your cervix, mimicking how your baby’s head would rest against it. This pressure will trigger the release of hormones (oxytocin and prostaglandin) that soften the cervix and stimulate contractions, which will eventually prompt labor to start. 14

You may feel a sharp but brief pain when your doctor inserts the catheter. Once the bulb is in place, it might feel like having a full or large tampon in. 12

It shouldn’t stop you from peeing or passing stool, and the pain should be manageable, not excruciating. However, the added pressure on your cervix may make your contractions more noticeable once they start.

You chat with your doctor about pain management options like nitrous oxide (laughing gas) to make the insertion itself more tolerable. 15 16

Foley bulb induction has a fairly high success rate. Roughly half of women who undergo it go into labor within 24 hours, with two-thirds delivering within 48 hours. The procedure “fails” a little over 10% of the time. 17

If it “fails,” that doesn’t mean you’ll have any of the issues listed above. Your doctor may just need to provide further intervention, like manually breaking your water (amniotomy) or performing a C-section. 6

How long will the Foley bulb take to induce labor?

After the Foley bulb is in place, you’ll usually just wait for it to do its job.

Active labor will hopefully start within 24 hours of the procedure, but bodies don’t always behave in predictable ways, and that isn’t guaranteed. 18 If you still fail to go into labor, your doctor will probably explore other induction methods. In the meantime, you may have some cramping and spotting.

How will the Foley bulb get removed from your body?

The balloon will probably fall out on its own, most likely when you’re about 3 to 4 centimeters dilated. 12 19 In most cases, this takes several hours.

If the catheter doesn’t fall out naturally, your doctor may manually remove it after 12–24 hours. 18 19 Ask your doctor whether they’d like you to come in if your Foley bulb falls out on its own or if it’s OK to wait for the onset of labor contractions.

Virtually no medical procedure is perfectly safe, and Foley bulb induction is no exception.

There’s a small risk of pregnancy complications from a Foley bulb induction, such as hyperstimulation (uterine contractions that are too strong, frequent, or long-lasting). 6 7 This can lead to further issues, such as bleeding or an umbilical cord prolapse.

Fortunately, the chance of excessive contractions with a cervical ripening balloon is less than 1% (in comparison to the 4%–5% rate with induction via certain synthetic hormones).

Foley bulb induction also carries a small risk of infection as the insertion can introduce bacteria to your body. 20

If your pregnancy is low-risk, Foley induction may be an outpatient procedure. This means you could be sent home while the bulb is still in place, depending on your situation and the hospital’s protocols.

Your hospital may not allow this if you have a medical condition that needs to be closely monitored, like preeclampsia, a heart condition, or a fever of at least 100.4 °F. 21

As mentioned, you may experience cramping and light spotting at home. Chat with your doctor about using pain relievers if you’re a little achy after the procedure.

If you have trouble sleeping, Benadryl is safe for pregnant women. 22 However, don’t exceed one dose every six hours, and never take it if you might need to drive.

It probably goes without saying that you should contact your doctor if and when you notice the signs of labor, like:

• Your water breaking
• Bloody or brown pregnancy discharge, known as “bloody show”
• Contractions every 3 to 5 minutes (each lasting 1 minute) over the course of 1 hour

You should also see your doctor immediately if you experience anything abnormal, such as if you: 7 18

• Have a fever over 100.4 °F or chills, indicating an infection
• Experience bleeding (beyond light spotting)
• Feel your baby kicking less than normal (fewer than 10 movements in two hours)
• Have difficulty using the bathroom

If your doctor needs to induce labor, using a Foley bulb is just one of several options.

They may use one of the other common methods, like: 23

• Medication: Your doctor may use synthetic hormones (e.g., prostaglandins or oxytocin) to encourage uterine contractions and cervical dilation.
• Membrane sweeping: They may use their fingers to separate your amniotic sac from your cervix, which also stimulates the release of hormones that encourage labor to begin.
• Amniotomy: If your water doesn’t break on its own, your doctor may need to use a small plastic hook to manually rupture your amniotic sac. This usually jump-starts labor within a few hours.

Foley bulb induction has several benefits over these methods; it’s low-risk, and it doesn’t require administering medication (which is always a plus, since all drugs can cause side effects). 6 7

Are all labor induction methods safe?

All medical induction methods are generally safe, and the “right” one depends on your situation. Before recommending a method, your doctor will consider whether your cervix has started to ripen already, whether you have any drug sensitivities, and so on. 24

Note that these methods also aren’t mutually exclusive. For instance, it’s possible that your doctor will opt for a Foley bulb in combination with synthetic oxytocin, or that they’ll try to get things moving with a Foley bulb and then proceed to an amniotomy if your baby still doesn’t show any signs of coming out.

No mom-to-be dreams of capping her pregnancy off with a Foley bulb induction. However, it’s relatively common and is nothing to panic about if it does become necessary.

While the procedure itself might be a little uncomfortable, it’s generally safe, and your doctor will be available to answer any questions you have about it. The whole thing will probably just be a tiny blip in your memory in a few days when you’re finally holding your baby in your arms.