Having a membrane sweep is a common procedure offered to women in the later stages of pregnancy to help bring on labor. It involves a healthcare provider sweeping their finger around the cervix to separate the membranes of the amniotic sac from the cervix. This action releases prostaglandins, which are hormones that can help to ripen and dilate the cervix in preparation for labor. While membrane sweeping is considered safe overall, there are some potential risks and side effects to be aware of.
What is a membrane sweep?
A membrane sweep, also called a stretch and sweep, is a procedure done late in pregnancy, usually around 38-40 weeks gestation. It involves the healthcare provider inserting a gloved finger into the cervical opening and rotating it in a circular motion to separate the amniotic sac membranes from the lower part of the uterus near the cervix. This separation releases prostaglandins, which are hormones that help ripen and dilate the cervix. A membrane sweep is thought to mimic the natural processes that occur before the onset of labor.
The goal of a membrane sweep is to encourage the cervix to thin out (efface) and open up (dilate). This can help stimulate contractions and kickstart labor. It’s estimated that membrane sweeping increases the likelihood of labor within 48 hours by 1.5 times. However, there are no guarantees that a sweep will successfully induce labor.
What are the potential benefits of a membrane sweep?
Some key potential benefits of having a membrane sweep include:
- May help start the process of labor
- Avoids using pharmacological methods like medication for induction
- More natural way to encourage labor
- Relatively quick, easy, and low-risk procedure
- Can be done in a prenatal visit – no hospital admission required
Studies show that membrane sweeping decreases the likelihood of still being pregnant past 41 weeks gestation. This can help reduce the risks of complications that are more common in post-term pregnancies.
Having a sweep means you may be able to avoid being induced with medications like Pitocin. The sweep is essentially a more natural way of starting labor physiologically rather than using drugs.
What are the risks and side effects?
While membrane sweeping is generally considered safe, there are some potential risks and side effects:
- Discomfort – The procedure can cause some mild to moderate discomfort or pain, especially if the cervix is still closed and firm. You may have menstrual-like cramping afterward.
- Spotting – Some light spotting or bleeding can occur after a sweep and is normal.
- Infection – Very small risk of introducing bacteria which could cause infection like chorioamnionitis. Providers will avoid sweeping membranes if the amniotic sac is broken.
- Accidental rupture of membranes – Rarely, a sweep could accidentally rupture the amniotic sac, breaking your water. The risk is estimated to be around 1-2%.
- Cord accident – There is an extremely small risk of a cord accident if the umbilical cord happens to be near the cervix when the provider does the sweep.
- Stimulating labor too early – Could start preterm labor if done too early. Sweeps are generally done at term at 38+ weeks or later.
- No labor stimulation – A sweep does not always successfully kickstart labor. Effectiveness rates are about 25-50%.
These risks are relatively small. Your provider will assess the risks and benefits based on your individual circumstances before recommending a sweep.
When is a membrane sweep recommended?
Membrane sweeping is typically recommended and offered sometime between 38-40 weeks gestation. The exact timing will depend on your provider’s practice and your preferences.
Some providers will offer it at any prenatal visit after 38 weeks as long as the cervix appears favorable. Others may wait until closer to your due date, like at 40 weeks.
It won’t typically be recommended prior to 38 weeks since the goal is ripening the cervix at term when baby is ready to be born. Doing it too early could risk preterm labor.
Your doctor may suggest scheduling a sweep earlier than your due date if there are medical reasons to deliver sooner, like gestational diabetes, preeclampsia, or a small-for-gestational age baby.
How is a membrane sweep performed?
The procedure for a membrane sweep is relatively quick and simple. Here is the basic process:
- You will have a prenatal checkup as normal. The provider will likely do an internal exam to check your cervix.
- They will insert one gloved, lubricated finger through the vaginal opening and cervical os.
- The finger will make a circular sweeping motion to separate the amniotic sac membranes from your cervix.
- This will stimulate local release of prostaglandins to ripen the cervix.
- The finger will be removed after rotating around for 15-30 seconds total.
The actual sweep generally takes less than a minute to perform. It can be done right at a regular prenatal visit. No additional preparation is required.
You may have some menstrual-like cramping, discomfort, or spotting afterward. This is normal. Your provider will let you know what to expect.
How often can membrane sweeps be done?
There is no set limit on how many membrane sweeps you can have, but they are generally not done more than once per week. This allows time for the effects of the initial sweep to work.
Repeated frequent membrane sweeping is not recommended since it can irritate the cervix. Doing too many sweeps may also increase the risks of side effects like infection.
Here are some general guidelines on frequency:
- One sweep at 38, 39, and 40 weeks is common if labor does not start on its own
- No more than 1 sweep per week in the 38-40 week range
- No more than 3-4 total sweeps recommended
Talk to your provider about an appropriate schedule if you are planning on having multiple sweeps before labor is induced or a cesarean delivery is planned.
What can boost the effectiveness of membrane sweeps?
Some things that may help improve the effectiveness of membrane sweeping include:
- Being at least 1-2 cm dilated when the sweep is done
- Having the sweep between 38-40 weeks gestation
- Already being effaced over 50%
- Having a ripe, soft cervix
- Being pregnant with your first child
- Having had a previous vaginal delivery
- Sexual intercourse
- Nipple stimulation
- Walking regularly
If your cervix is still closed and firm, the sweep may not be as effective. Your provider can give guidance on if your cervix seems favorable.
Doing things like nipple stimulation, sex, and walking can all help release natural prostaglandins as well to add to the effects of the sweep. Staying well hydrated can also help.
What happens if the sweep doesn’t work?
While membrane sweeping does have good effectiveness rates overall, there is always a chance it may not successfully initiate labor. Here’s what may happen next if a sweep or multiple sweeps don’t bring on labor:
- Wait and see if natural labor starts in the next several days to week
- Schedule additional sweep(s) at future prenatal visits
- Elective induction of labor at 40-41 weeks
- Planned cesarean delivery if induction is not desired or recommended
Many providers will give a timeframe like 1-2 weeks after the 40 week mark before moving to scheduled induction or cesarean delivery. How long you wait will depend on your circumstances.
If you go into your due date or beyond, monitoring baby with nonstress tests and biophysical profiles can help check on their wellbeing as you wait for labor.
Are there any conditions where a sweep would be avoided?
There are some cases where membrane sweeping may not be recommended or would be avoided:
| Condition | Reason sweep avoided |
|---|---|
| Premature rupture of membranes | Risk of infection |
| Placenta previa | Risk of bleeding |
| Vasa previa | Risk to cords |
| Active vaginal bleeding | Underlying cause needs identified |
| Herpes outbreak | Risk of neonatal herpes transmission |
Your provider will evaluate whether sweeping is a good option based on your health conditions and risks. Other precautions may include avoiding them before 39 weeks in first time moms to lower early delivery risks.
How effective is membrane sweeping?
Studies looking at the effectiveness of membrane sweeping have found:
- Around 25-50% of women go into labor within 24-48 hours after membrane sweeping
- Sweeping reduces the frequency of pregnancies extending beyond 41 weeks compared to no sweeping
- Women who had sweeping were less likely to need formal induction methods
- More effective in women who have already had a vaginal delivery before
- Less effective for first time moms, but can still help ripen the cervix
So while not universally effective, membrane sweeping does significantly increase the chances of avoiding post-term pregnancy complications and interventions like induction.
Many factors play a role, which is why providers may recommend doing multiple sweeps if needed at weekly intervals. Overall, it’s a safe option with minimal risks that may help trigger the natural onset of labor.
Frequently Asked Questions
Is getting a membrane sweep painful?
Membrane sweeping is typically not very painful, but it can cause some mild to moderate discomfort since it involves placing a finger inside the cervical opening. Many women say it feels like a Pap smear with stronger cramping afterward. The whole process only takes about a minute or less.
What percentage of membrane sweeps work?
Studies show membrane sweeping works to initiate labor within 24-48 hours for around 25-50% of women who have it done. Success rates are higher if the cervix is already ripe and favorable. For first time moms, the success rate may be toward the lower end around 25%.
What should I expect after a membrane sweep?
It’s common to have some cramping, menstrual-like discomfort, or light spotting after having a membrane sweep. You may also have some vaginal discharge. Other common symptoms include diarrhea, nausea, or feeling emotional. These effects are caused by prostaglandin release and usually resolve within a day or so.
Can a membrane sweep break your water?
While not common, a membrane sweep does carry a small risk of accidentally rupturing the amniotic sac and membranes, which is also called breaking your water. This risk is estimated to be around 1-2%. Let your provider know right away if you think your water has broken after a sweep.
Can a membrane sweep cause bleeding?
Some light spotting or bleeding can happen after a membrane sweep, but it’s usually mild. Heavy bleeding after a sweep is not typical and could be a sign of complications like placenta previa or vasa previa. Contact your provider if you have heavy vaginal bleeding.
Can membrane sweeping cause infection?
There is a low risk of introducing bacteria that could cause infection like chorioamnionitis or sepsis from membrane sweeping. To reduce infection risks, it will not be done if your membranes have already ruptured. Proper technique by your provider also minimizes any risks.
How often can you get a membrane sweep?
There are no strict limits, but membrane sweeps are typically not done more frequently than once per week between 38-40 weeks gestation. Too many frequent sweeps can irritate the cervix. No more than 3-4 total sweeps are recommended to reduce potential risks.
Can a membrane sweep harm the baby?
Membrane sweeping is considered safe for the baby and serious risks are very rare when done by a skilled provider at term. There is an extremely small chance of accidentally snagging the umbilical cord if it happens to be near the cervix during the sweep. Overall, it will not directly harm the baby.
Is a sweep uncomfortable for the baby?
A membrane sweep may cause some mild discomfort for the baby since it can stimulate uterine cramping with the release of prostaglandins. However, it’s very brief and will not harm or distress the baby in any significant way. Fetal monitoring after a sweep shows minimal effects on the baby’s heart rate.
Conclusion
Membrane sweeping is an effective and safe option many providers recommend to help encourage the natural onset of labor at term. While the procedure can cause some discomfort, the risks are low and a sweep may help avoid being induced. Talk to your prenatal care provider about whether membrane sweeping is appropriate for your situation. Although not guaranteed to work, it boosts the chances of going into labor without additional medical interventions.