If you’re getting close to your estimated due date—which is just a guess by the way—something you may have heard about is membrane sweeping, also sometimes called membrane stripping. These terms get thrown around a lot, but don’t always get explained. Read on to learn more about what you can expect if you get your membranes swept and what the advantages and disadvantages are.
Membrane sweeping is a physical induction method, intended to promote cervical softening and opening. Another method along these lines is foley catheter or foley bulb induction, which is when a small balloon is used to open your cervix. Unlike insertion of a foley bulb, though, membrane sweeping can be done more than once in the weeks around the due date. The membrane sweep usually takes place during a vaginal exam or cervical check in your care provider’s office or at the hospital, if you’re already there for some reason.
During the membrane sweep, your provider will insert a finger in your vagina. If your cervix has begun to open, they will reach the finger inside and use a swirling motion to loosen the connection between the sac holding baby and your cervix. If your cervix is closed, they may massage the cervix to help it soften and open.
In a February 2020 Cochrane Review, midwife and researcher Elaine Finucane and her coauthors analyzed 44 scientific studies exploring the effectiveness of membrane sweeping in inducing labor. Overall, they found that membrane sweeps may promote labor and may lead to fewer medical inductions, but that there is no evidence that membrane sweeping leads to a greater chance of having a vaginal birth as opposed to a cesarean birth.
In one clinical trial published in Obstetrics & Gynecology in 2006, a team led by physician Peng Chiong Tan determined that a membrane sweep that accompanied a medical induction increased the number of subjects who experience spontaneous vaginal deliveries, reduced the use of synthetic hormones like Pitocin, shortened the time from induction to delivery, and led to more satisfied patients. And in another study published in the Sri Lanka Journal of Obstetrics and Gynaecology in 2019, physician Samantha Yaddehige and colleagues found that both cervical massage and membrane sweeps were capable of softening and opening the cervix, as compared to no intervention.
These reported advantages might be worth it to you, but there are also potential drawbacks. Sometimes having your membranes swept is uncomfortable, even painful, but sometimes you won’t feel anything. Another potential issue is that if your cervix is open during a membrane sweep, it is possible that your membranes or bag of waters could be artificially ruptured.
In a clinical trial published in the journal Obstetrics & Gynecology in 2008, physician Micah Hill and colleagues found that subjects who received a membrane sweep were more likely to experience their waters breaking before labor started. If your water breaks before labor starts, most care providers will want labor to start within 24 to 48 hours. If it does not, you will be offered medical induction, likely in the form of synthetic hormone Pitocin, which can lead to a different experience of labor and birth.
According to nurse and researcher Rebekah Dekker, writing at her website Evidence Based Birth, another possible drawback is that care providers may perform a membrane sweep without your consent, as part of a vaginal exam during late pregnancy. Before doing a membrane sweep, your doctor or midwife should let you know that it is an option and ask whether you would like to have your membranes swept. Your care provider should also make time for you to ask questions. If you do not want a membrane sweep, you can refuse and also opt out of vaginal exams and cervical checks completely.
If you’d rather try other things before a membrane sweep, check out this blog post from The Pulse about natural induction methods. Another helpful post is this one about questions to ask your doctor or midwife before an induction. While a membrane sweep is not a full-fledged induction, it is a definite nudge toward your baby coming sooner rather than later.