iBRAIN and Membrane Sweeping

by Asheya on March 12, 2013

by Lisa Baker

In our February 19 blog post, we discussed the elements of informed decision making. Today we will use the iBRAIN framework to analyze the stripping or sweeping of membranes as a form of labour induction.


Membrane sweeping or stripping is a relatively simple procedure that can be performed by your doctor or midwife during a regular prenatal checkup. During a vaginal exam, your care provider will insert a finger into the cervix and move the finger around in a circular motion. As the finger moves around in a circle, it lifts the amniotic sac away from the lining of the uterus. It is currently believed that this lifting of the sac stimulates the production of prostaglandins. Prostaglandins are hormone-like substances that can cause smooth muscle to contract. A high concentration of prostaglandins near the cervix can help ripen (soften and thin out) the cervix and even stimulate labour contractions. It is possible to have your membranes stripped more than once if necessary.


  • Stimulates production of your own prostaglandins rather than using a synthetic form
  • This can be done without be admitted to the hospital
  • It can be repeated if necessary
  • Research has shown that sweeping of membranes between 38-40 weeks gestation decreases the number of pregnancies continuing past 41 weeks
  • Research has shown that sweeping of membranes can reduce the frequency of using other formal induction methods such as cervical ripening agents and synthetic oxytocin
  • When compared to no intervention, membrane sweeping did not lead to an increase in amniotic sac ruptures or in maternal or fetal infections


  • Women have reported the procedure to be uncomfortable and even painful
  • Spotting (small amounts of dark red or brown blood) is common
  • Uterine irritability for 24 hours after the procedure is common (uterine irritability means the uterus contracts without going into labour)
  • It is not the most effective way to stimulate labour. It may or may not begin labour. Even if it is responsible for starting labour, it can take days before labour starts. If there are urgent medical concerns with you or your baby that require an induction of labour then other forms of labour induction should be considered



Note that each of the following alternatives has a set of risks and benefits. Some of these alternatives will be reviewed in future posts. Be sure to talk to your doctor or midwife if you have questions or wish to discuss any of these forms of labour induction.

  • Castor Oil
  • Breast/nipple stimulation
  • Breaking the amniotic sac (amniotomy)
  • Prostaglandin (to ripen cervix and perhaps stimulate contractions)
  • Foley catheter to open (dilate) the cervix
  • Pitocin (synthetic form of oxytocin, the hormone that stimulates contractions)
  • Accupressure

Which induction method to use depends on your individual circumstances, including your health, readiness of your uterus, rupture of amniotic sac, and health of the baby.


Women who choose not to use membrane sweeping will continue to wait for labour to begin on its’ own if mom and baby are both healthy. This is the recommended approach for healthy pregnancies. If there is a health concern that requires an immediate induction, more effective forms of induction in a hospital setting should be considered.

Please note that at the end of pregnancy, you may feel anxious to be done with pregnancy and see your baby. However, labour is safest for you and your baby if it is allowed to begin on its own. The current research suggests there is no real need for membrane stripping. If induction is required due to health concerns more effective methods should be considered. Otherwise, it is best to wait for labour to begin on its own.



(1)  Boulvain M, Stan CM, Irion O. Membrane sweeping for induction of labour. Cochrane Database of Systematic Reviews 2005, Issue 1. Art. No.: CD000451. DOI: 10.1002/14651858.CD000451.pub2.

(2)  http://www.childbirthconnection.org/article.asp?ck=10652

{ 2 comments… read them below or add one }

Kat March 12, 2013 at 12:04 pm

“When compared to no intervention, membrane sweeping did not lead to an increase in amniotic sac ruptures or in maternal or fetal infections”
I find the above point very interesting and I wonder what the actual data shows for sweeps that resulted in rupture of the amniotic sac. It may be considered anecdotal evidence, but significant or not, there is a chance that a membrane sweep may lead to the premature rupture of membranes. This is important info for women to know, because if the membranes rupture and labour does not begin within a time frame their care provider is comfortable with (usually 24-36 hours), a medical induction is the next step. And as we know, the cascade of interventions that begins with induction can sometimes lead to unexpected and unwanted outcomes. While it certainly is not always the case that the membranes will rupture after a sweep, I think it’s a point to consider when making the decision of whether or not to go ahead with a consenting to a sweep.


Lisa Baker March 16, 2013 at 9:22 pm

Hi Kat,

You bring up a very valid point and one that is important for expectant mothers to know.

Have women had their water break prior to contractions beginning with membrane sweep? Yes.

When the investigators reviewed the relevant studies of 2389 women, they did not find a significant difference between pre labour rupture of membranes among women who had a membrane sweep and those who did not have a membrane sweep. The relative risk (RR) of prelabour rupture of membranes in the membrane sweeping group was RR: 1.14; 95% CI: 0.89 to 1.45. This means that although the relative risk was higher than 1 (more women had rupture of membranes in the membrane sweeping group), the confidence interval (CI) dipped below 1.0 and because of this the authors can not conclude it is a significant difference. This result should be interpreted with caution, as there are over 11 newer studies that have not yet been included in the Cochrane review. I imagine that the numbers we see in the review will change once they include these more recent studies.

Again, thank you Kat for sharing this point!



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