Stripping, Stretching, Sweeping – You Want To Do What?

Sweeping, stretching and stripping all sound a bit scary, after all one’s lower uterus is not used to getting much action. Sweeping of the membranes, also called stripping or stretching, is a procedure performed during a vaginal exam.  A finger is placed into the cervix,  then in technical terms, “the inferior pole of the membranes is detached from the lower uterine segment by a circular movement of the examining finger”.* In lay terms that means that a finger is placed through the cervix and separates the membranes of the amniotic sac from the bottom part of the uterus, lifts it up a bit and a finger is run around the exposed diameter.  The agitation of this area and manipulation of the membranes may cause the body to increase production of  prostaglandins, ie the hormones that are thought to ripen the cervix in preparation for labor.

Studies do show that having the membranes swept can create clinically significant results.  If done at each appointment from 38 weeks on, membrane sweeping was shown to slightly reduce the number of pregnancies that go past 41 and 42 weeks.  However, as most pregnancies will not go past 42 weeks anyway this information has limited significance for the average expectant woman. The studies also showed that membrane sweeping did somewhat reduce the need for other means of induction such as the use of prostaglandins or oxytocin/pitocin.  What the studies don’t say is why those inductions were needed.  If they were needed because the pregnancy had a medical need to end and this procedure helped end those pregnancies safely with less intervention- then this is great news.  However if it means we have found yet another way to end a thriving pregnancy- that really isn’t great news at all.

Membrane sweeping may not seem like a big deal as many providers do routine vaginal exams the last weeks of pregnancy anyway (my post on routine vaginal exams) so a more vigorous exam doesn’t seem like a big step to take, but it is an intervention.  The sweeping is usually uncomfortable as it is basically a vaginal exam on steroids and often produces light bleeding or spotting afterwards.  Membrane sweeping can lead to irregular, uncomfortable but ultimately unproductive contractions that are only capable of disrupting mom’s prospects of a good night’s sleep…but not actual labor.  At worst the procedure can cause the baby’s amniotic sac to rupture which can mean a premature baby if the stripping was done shy of term or lead to an unnecessary induction and/or c-section. The risk is also higher that GBS will be passed on to the baby when membrane stripping is done on women who are GBS positive.

However, membrane sweeping is one evidenced based methods that does *sometimes* stimulate labor without the use of more invasive or higher risk means such as cytotec or pitocin and sometimes inductions really are indicated or desired (though it needs to be kept in mind that membrane sweeping is not a sure thing).  The membrane sweeping can create a situation where the body is tricked, so to speak, into producing more of its own hormones in hopes of avoiding the use of synthetic hormones.  Another huge bonus is that it can be done in the office rather than the hospital.  Some care providers do routine membrane stripping starting at 37 weeks, some suggest it only when a mom has a prior history of a post dates pregnancy and some will only use it when there is a need to encourage the pregnancy to end for either the health of mom or baby.  In any instance, it is very uncool for a care provider to strip a woman’s membranes without obtaining consent!