Membrane sweeping is a mechanical method of labor induction. Some people refer to it as a “mean sweep,” but I do not identify with that term.
When Should Membrane Sweeping Be Considered?
It is usually done during an obstetric appointment, after informed consent, with the intention of encouraging the onset of labor. For that reason, it should only be performed when there is a reason to induce labor or by maternal choice from 39 weeks onward.
How Is Membrane Sweeping Performed?
During a vaginal examination, the healthcare professional inserts a finger through the cervix until reaching the membranes surrounding the baby and, with a circular motion, separates the membranes from the uterine wall. If the cervix is closed, the procedure cannot be performed. It lasts only a few seconds, and the pregnant woman may ask for it to be stopped at any time.
The illustration shows only one finger, but in practice it is usually performed with two fingers inserted into the vagina (the index and middle fingers).
Do not confuse this with placental abruption (which is unexpected and an emergency) or with rupture of membranes (“water breaking”).
Tolerance and Effects of This Induction Method
In my experience, the procedure is usually well tolerated. Most women report a sensation of strong pressure during the sweep and sometimes experience a pinkish or brownish vaginal discharge afterward.
A meta-analysis shows a reduction in induction rates (23% vs 31%) and an increase in “spontaneous” labor onset (72% vs 60%) in the membrane-sweeping group, without worsening maternal or neonatal outcomes.
Membrane sweeping also reduces the likelihood of reaching 42 weeks of pregnancy when performed at 41 weeks.
Having Group B Streptococcus or a previous cesarean section is not a contraindication for performing a membrane sweep.
In my practice, I usually suggest a membrane sweep when we are planning hospital admission soon for labor induction, as a final attempt to trigger labor outside the hospital setting.