A membrane sweep, also known as a stretch and sweep, is a procedure done late in pregnancy to try to induce labor. It involves your doctor or midwife putting a finger inside the cervix and rotating it to separate the membranes of the amniotic sac from your cervix. This releases prostaglandins, which are hormones that help ripen and dilate the cervix to prepare it for labor. While generally considered safe, some women wonder if a membrane sweep can harm the baby.
What is a membrane sweep?
A membrane sweep, or stretch and sweep, is a vaginal examination done by your doctor or midwife. During the exam, they will put a gloved, lubricated finger into your cervix and rotate it in a circular motion to separate the membranes of the amniotic sac from your cervix. This separation releases prostaglandins, which are hormones that help soften and thin out the cervix. It also can stimulate local production of prostaglandins.
The goal of a membrane sweep is to initiate the hormones and changes needed for labor. It may kick start early labor, especially if your body is already ready. While not always effective at starting labor, some research shows it can prevent you from going too far past your due date.
Membrane sweeps are typically done starting around 38-40 weeks of pregnancy. Your doctor or midwife may do several of them leading up to when labor should begin naturally. They are safe, cause minimal discomfort, and may save you from being induced if labor is late.
Can it harm the baby?
In general, membrane sweeps are considered safe for both mom and baby when done by a skilled provider at the appropriate time. However, there are some concerns about potential risks, including:
Infection risk
Putting a finger in the cervix does disrupt the protective mucus plug sealing off the uterus. This could introduce bacteria and increase the risk of infection. However, the risk is low if proper hygiene and sterilization practices are used. Providers should always wash hands thoroughly and wear sterile gloves.
If you have symptoms of infection after a membrane sweep, such as fever, foul-smelling discharge, or abdominal pain, contact your provider right away. You may need treatment with antibiotics.
Placental abruption
There is a small risk that separating the membranes could cause the placenta to partially detach from the uterine wall. This is called placental abruption. However, there are no studies proving membrane sweeps increase placental abruption. The risk is extremely low.
Placental abruption can block oxygen flow to the baby. Symptoms include vaginal bleeding, back or abdominal pain, and tenderness of the uterus. It requires emergency medical care.
Breaking the amniotic sac
It’s possible the membrane sweep could accidentally rupture the amniotic sac. This causes the release of amniotic fluid, known as your water breaking. If this happens before 37 weeks, it is called preterm premature rupture of membranes (PPROM).
PPROM raises risks of a dangerous umbilical cord compression and infection in the womb since fluid levels are reduced. Babies born too early are also at higher risk for complications with their lungs, brain, and other organs.
However, as long as sterilization procedures are followed, the chances of a membrane sweep causing PPROM are extremely unlikely. Studies show no increase in PPROM from membrane sweeping.
Stimulating early labor
While the goal of a sweep is to induce labor hormones, there is a chance it could stimulate labor before the baby is ready to be born. If contractions start, the provider may try to stop labor with medications if it is too early.
Doctors and midwives avoid doing sweeps too early unless medically necessary. They also typically avoid them if the cervix is still closed and firm, as labor is unlikely to be triggered.
Cord prolapse
Rarely, inserting fingers into the cervix could cause the umbilical cord to slip down and protrude out. This is an emergency called cord prolapse. Pressure on the cord cuts off the baby’s oxygen supply.
Cord prolapse generally only happens if the amniotic sac is already ruptured. The risk from a membrane sweep alone is extremely minimal.
Pain or bleeding
You may have some mild cramping or spotting after a membrane sweep. More severe pain or heavy bleeding is uncommon. Alert your provider if you have signs of excess bleeding, as it may indicate a problem.
Is the procedure optional?
Membrane sweeps are recommended when you go past your due date in order to help get labor started naturally. However, they are not required. You can decline them if you have concerns about risks or are not comfortable with the procedure.
Talk to your OB-GYN or midwife about the pros and cons. Let them know if you want to avoid membrane sweeps or want them only done when medically warranted. Make sure you understand why they are advising it so you can give fully informed consent.
There are some situations where your provider may highly recommend membrane sweeps, such as if there are medical concerns requiring the baby to be born soon. However, you always have a choice and voice in your care decisions.
How often can they be done?
There are no strict limits on how many membrane sweeps you can have. However, they are typically only done after 37 weeks and no more than once a week. Doing them too often increases the chance of infection or other complications.
Your OB-GYN or midwife will assess if your cervix is favorable before each sweep. If it is still closed and firm, additional sweeps may not accomplish much. You can decline any sweeps you are not comfortable having.
Are there any restrictions?
Membrane sweeps are not recommended in certain situations that increase possible risks:
- Before 37 weeks gestation when the baby is premature
- If you are bleeding or have problems with the placenta
- If the amniotic sac has ruptured
- If you have an infection or sexually transmitted disease
- If the baby is in an abnormal position like breech
- If you have a low-lying placenta (placenta previa)
Make sure your provider is aware of any medical conditions or complications you have had with your pregnancy. This will determine if membrane sweeps can be done safely.
Can it be done at home?
It is strongly advised that membrane sweeps only be performed by a trained medical professional like an OB-GYN, midwife, or family medicine doctor. Improperly sweeping the membranes on your own could lead to infection or accidentally rupture the amniotic sac. Leave the procedure to your provider.
How to prepare
Membrane sweeps are simple and take less than a minute to perform. Here are some tips for preparing:
- Drink plenty of water before your appointment to fill up your bladder
- Have someone drive you just in case you have cramping or contractions
- Take a pain reliever beforehand if recommended by your provider
- Wear a pad in case of any bleeding or discharge afterwards
- Relax your body during the exam for comfort
- Discuss using sterile gloves to lower infection risks
What to expect during the procedure
During a membrane sweep:
- You will lie down on the exam table with your knees bent or feet in stirrups
- The provider will insert two gloved, lubricated fingers into your vagina and uterus
- They will use the fingers to rotate and gently separate the amniotic sac from your cervix
- You may feel some stretching or pressure during the sweep
- The procedure takes less than a minute
- You can get up right away and resume normal activities
Let your doctor know if you feel any intense pain or abrupt gush of fluid, as those may indicate a problem. Otherwise, mild cramping and discharge are common afterwards.
What happens after the sweep?
Some women go into labor within hours or days of a membrane sweep, while others may not for over a week. Here is what to expect:
- Mild cramping and spotting are common
- Contractions may start as your body releases natural labor hormones
- Your water could break soon if it was close to rupturing already
- Wait for regular contractions 5 minutes apart lasting 1 minute before going to the hospital
- Labor may not happen yet if your cervix was not ready – additional sweeps or induction may be needed
- Call your doctor if you have heavy bleeding, intense pain, or signs of infection
Keep in touch with your provider about any changes you notice. Avoid sexual intercourse, baths, and douching until after delivery as they increase infection risk.
What if it doesn’t work?
Membrane sweeping does not successfully induce labor for everyone. Factors like an unfavorable cervix reduce the chances it will work. Here are your options if sweeping does not kick start labor:
- Have additional membrane sweeps done by your provider if appropriate
- Discuss being induced with medications like Pitocin or misoprostol if you go too far past your due date
- Wait for labor to begin naturally if there are no medical concerns
- Strip or sweep your own membranes is not recommended
Talk to your OB-GYN or midwife about your willingness to have more sweeps or medical induction. Monitor the baby’s movement and have regular nonstress tests to ensure they remain healthy if you go post-term.
Success rates
Studies show that membrane sweeping increases your chances of going into labor within 48 hours. However, how well it works can vary:
- Around 20-30% of women go into labor within 48 hours
- Higher success rates are seen the closer you are to your due date
- First-time moms have lower rates of success compared to second or third-time mothers
- Your Bishop score, a measure of cervical favorability, also impacts success
- Having multiple membrane sweeps increases your overall chances
While not always effective, membrane sweeps are a safe option before resorting to medical induction methods. Many providers recommend trying them before any other labor stimulants.
Pros and cons
Here is a summary of the main advantages and disadvantages of membrane sweeping:
Pros
- May stimulate labor hormones and contractions
- Avoids risks of medications used in medical inductions
- Quick and easy procedure for the provider to perform
- Helps avoid going too far past your due date if successful
- No major risks or side effects in most cases
Cons
- Does not work for everyone
- Causes some mild discomfort during the exam
- Small risks like infection, bleeding, waters breaking too soon
- Labor may stall requiring induction anyway if cervix is not ready
- May trigger very early labor if done prematurely
Discuss the advantages and potential risks with your OB-GYN or midwife when deciding if membrane sweeps fit into your birth plan.
Frequently asked questions
Here are answers to some common questions about membrane sweeps:
Are membrane sweeps the same as stripping membranes?
Yes, membrane sweeping and stripping membranes are two terms for the same procedure. They both involve inserting fingers into the cervix to separate the amniotic sac membranes.
Can it cause any bleeding?
You may have some light bloody discharge or spotting after a sweep. Heavy bleeding is uncommon but let your provider know if you are concerned about the amount.
Do they hurt?
Some women report membrane sweeps being mildly uncomfortable or causing period-like cramping. However, it is typically not very painful and only takes a few seconds.
When will a sweep be offered?
They are typically first offered anytime from 38-40 weeks and onward. Your provider will check if your cervix is favorable before doing them.
Can a sweep harm the baby if done too early?
Yes, membrane sweeps before 37 weeks can pose risks if they accidentally initiate early labor before the baby is ready. Providers avoid doing them prematurely unless medically urgent.
How long do you have to wait between sweeps?
There is no exact required spacing, but they are usually done no more than once per week. Your provider will determine appropriate timing based on cervical changes and other factors.
The bottom line
While not completely risk-free, membrane sweeps are considered safe as long as proper precautions are taken and they are not done too prematurely. Serious complications like infection or placental abruption are very unlikely. Discuss any concerns with your OB-GYN or midwife so you can make an informed decision about whether membrane sweeping fits into your birth plan.