Stripping the Membranes to Induce Labor

Is the induction technique safe and effective?

Man helping wife deliver baby
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Stripping (or sweeping) of membranes is a manual technique used to start labor. The technique involves placing a finger inside the opening of the cervix and separating the membrane (amniotic sac) from the uterus. The goal is not to break the water but to stimulate the body in such a way as to trigger labor contractions. This is easily done while performing a vaginal exam.

Why Stripping of Membranes Is Done

The stripping of membranes is a technique long used by midwives when a pregnancy is abnormally prolonged.

Today, doctors and midwives will recommend the procedure if continuing the pregnancy poses any danger to the baby.

One such instance is when a pregnancy is approaching 42 weeks. By this stage, the food and oxygen in the placenta are being rapidly depleted. This can increase the risk of serious fetal complications, including:

  • Placental insufficiency (where not enough nutrients are being delivered to the baby)
  • Fetal hypoxemia (where not enough oxygen is being fed to the baby)
  • A steep drop in immune cells (corresponding to an increased risk of infection)
  • Decreased cardiac output (where not enough blood is being pumped through the body)
  • Limb abnormalities like clubfoot or hip dysplasia
  • Umbilical cord compression
  • Meconium aspiration syndrome (where the infant's first stool, or meconium, is accidentally inhaled into the lungs)

Conditions like these can place the baby at an increased risk of illness, disability, and stillbirth.

Risks of a Prolonged Pregnancy in Mothers

Most women deliver their babies by 41 weeks of pregnancy. Fewer than three percent will go beyond 42 weeks. If a pregnancy has extended to or beyond the 42-week threshold (294 days), it is deemed a prolonged (or post-term) pregnancy.

The risks of a post-term pregnancy include:

  • Obstructed labor
  • Perineal damage
  • Forceps delivery
  • Cesarean section
  • Postpartum hemorrhage
  • Infection

How Stripping of Membranes Is Done

Depending on the situation, the stripping of membranes may be done all at once or gradually over time. In some cases, your doctor or midwife may strip the membrane a little each week. In cases of prolonged pregnancy, this may be done every two days or all at once.

Having your membranes stripped does not cause an immediate reaction and, in some cases, may not induce labor all. If this happens, other methods of induction may be needed, including amniotomy (breaking the water) and the artificial hormone Picotin (oxytocin injection).

The procedure itself can be uncomfortable. Many women will report spotting or bleeding for up to three days later. Others may experience mild cramping or have irregular contractions.

Risks and Safety

As with any form of labor induction, the stripping of membranes carries the risk of infection, excessive vaginal bleeding, and the unintended rupture of the amniotic sac. However, the risks are considered relatively small for both the mother and baby if performed by a qualified health professional.

Even claims that stripping can pose serious health risks in women with group B strep (GBS) have been largely exaggerated.

According to a 2011 study from George Washington University, pregnant women who tested positive for GBS had no difference in outcomes after undergoing the procedure than those who didn't.

Sources:

Boulvain, M.; Stan, D. and Irion, O. " Membrane sweeping for induction of labour." Coch Data Sys Rev. 2010; 1: CD000451. DOI: 10.1002/14651858.CD000451.pub2.

Keller, J.; Ojo, L.; Sheth, S. et al. "Membrane sweeping in GBS positive patients: a randomized controlled trial." J ACOG. 2011; 204(Suppl 1): S41-S42. DOI: 10.1016/j.agog.2010.10.086.

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