Stripping the Membranes to Induce Labor

What Is Stripping the Membranes?

Stripping the membranes is a simple technique used by a doctor or midwife to start labor by manually separating the amniotic sac (or membranes) from the uterus. It's usually used when pregnancy is prolonged past term. The technique, which is also called sweeping the membranes, involves placing a gloved finger inside the opening of the cervix and moving the membrane away from the uterus.

The goal is not to break the water but to stimulate the prostaglandins in the uterus to trigger labor contractions.

Why Membrane Stripping Is Used

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.

Risk of Prolonged Pregnancy to Babies

There are growing risks for the baby when a pregnancy approaches 42 weeks. By this stage, the oxygen in the placenta is being rapidly depleted. This can increase the risk of serious fetal complications, including:

• 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)
• Fetal hypoxemia (where not enough oxygen is being fed to the baby)
• Limb abnormalities like clubfoot or hip dysplasia
• Meconium aspiration syndrome (where the infant's first stool, or meconium, is accidentally inhaled into the lungs)
• Placental insufficiency (where not enough nutrients are being delivered to the baby)
• Umbilical cord compression

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

Risks of Prolonged Pregnancy to Mothers

About 6% of pregnancies will go beyond 42 weeks. If 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 for the mother include:

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

Benefits of Membrane Stripping

This technique is primarily used to reduce the incidence of post-term gestation. It has been found to be effective at inducing labor for the majority of women. Effects are not instantaneous and may take several days or a week. Studies show that, on average, women who had their membranes stripped went into labor several days earlier than those in the control group.

This procedure is often used before or instead of other induction techniques, particularly for those that may prefer to avoid other more invasive intervention methods or using medications like Pitocin.

How a Membrane Sweep 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 at a time. In cases of prolonged pregnancy, this may be done every two days. If you're already in the hospital for labor but your labor is moving slowly or stalled, the procedure may also be done.

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

The procedure itself takes just minutes to perform. It can be mildly painful for a pregnant woman but feels similar to having a pap smear. Note that any sensation in the pelvic area is likely to feel more uncomfortable when you're at or near your due date.

Safety of Stripping Membranes

As with many methods 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. In fact, a 2019 review study found no significant difference in the incidence of complications—and that doing so reduced the need for other induction measures.

At one time, the procedure was thought to be risky for women with group B strep. However, research shows no adverse effects of membrane sweeping in these patients. In fact, 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.

A Word From Verywell

This procedure, while it can be uncomfortable, may be an effective, low-risk way to start labor without the use of medicines. So, sweeping the membranes may be appealing to both women and health care providers in cases where labor has not started after the due date.