Sweeping or stripping of the membranes
What you need to know because your care provider won't tell you ...
If there was one ritual I'd like to see banned before 40 weeks, it's the stretch-and-sweep, aka membrane stripping.
The routine stretch-and-sweep is performed during a vaginal exam at any time beginning around 37 weeks. Mothers are seldom told it was done. And rare is the mother who is actually given enough information to make a wise decision. Even if she declines this procedure, it's often done without her consent.
A stretch-and-sweep involves having the provider's gloved fingers manually stretch open the cervix and then strip the baby's amniotic sack away from the cervical opening. The baby's amniotic sack is normally adhered to the opening of the cervix in a way that prevents infectious agents from reaching the baby. It's one of pregnancy's many safe-guards.
It's believed that manually dilating the cervix and separating the sack from the opening of the cervix will release extra prostaglandins that could stimulate labour.
Only prostaglandins don't trigger normal labour. It's a hormone that ripens the cervix. It's actually the baby's lungs that trigger labour when they secrete a protein just when they're ready for air-breathing. Then oxytocin from mama's brain brings on contractions.
A membrane stripping is intended to "prevent induction". What your provider is saying to you (if they tell you) is:
"I will perform a mechanical induction to start labour artificially so that you might avoid a chemical induction after your due date with IV oxytocin in the hospital."
Yes. A stretch-and-sweep is an induction that is meant to "prevent" induction. It is meant to bypass your baby's lungs and all of the safety mechanisms of human birth to get the baby out before the baby is ready.
It makes you bleed.
It can cause your water to break meaning you now are expected to go to the hospital for a chemical induction.
It can introduce infection.
It begins non-labour, disorganized, painful, non-dilating contractions most of the time.
Your provider will say that you are in labour with these induced painful non-dilating contractions.
You will be sent to the hospital for augmentation and may end up with a caesarean for failure-to-progress.
Some studies say that doing a membrane stripping doesn't shorten pregnancy. Other studies say it can shorten pregnancy by a couple of days. All studies say it introduces many risks to you and your baby.
And since many providers won't tell you that they're going to do it I encourage you to decline a stretch-and-sweep, but also decline every vaginal exam prior to labour. Those exams have no benefit, give you no useful predictive information and introduce many risks.
That being said your doctor or midwife might suggested at around 41 weeks to indeed start things up, and with this knowledge you can choose if it is something for you.