Google+ Authentic Parenting: Do I Need to Get My Membranes Stripped at 41 Weeks Pregnancy?

Wednesday, March 27, 2013

Do I Need to Get My Membranes Stripped at 41 Weeks Pregnancy?

BannerFans.comMany care givers will suggest stripping of the membranes when a mother goes postdue. Generally this is offered at 41 weeks. Here are a few considerations about this topic in order to make an informed decision:

What is it?

Stripping the membranes is sometimes referred to as sweeping the membranes. It is a medical procedure which detached the amniotic sac from the uterine wall. This procedure is performed by inserting a finger into the cervix and then gently prying the amniotic sac off the uterince wall.
This procedure is done during a pelvic exam and it's goal is to start labor.
Membrane stripping can be painful for the mother and can cause painful cramping before actual labor starts.

The issue with due date and term

First of all, we need to address the issue of the due date and the generally accepted term of a pregnancy, we'll find that a due date is a guess at best.

the moment of conception

It is nearly impossible to know at what time exactly the baby was conceived. Even if the couple know when mom ovulated or when they had the fruitful sexual encounter, the actual conception can be at least 24 hours away from ovulation and within three days of intercourse. So even if you're very sure about this, you can be one or several days 'off'.
It's a common known fact that a due date is actually more of a due month, as most babies are born within the period two weeks before or after the due date.

duration of a pregnancy

People tend to say a pregnancy lasts 9 months, or 40 weeks (if you calculate, you'll find that 40 weeks is over nine months, so we already have a discrepancy here). If you visit your midwife or doctor's office, most likely they will determine your 'due date' based on this idea of 40 weeks.
But these 40 weeks are a false premises! They have been coined based on so called 'evidence' in the bible of a pregnancy lasting for 10 lunar months. And even then, the 10 lunar months have been misinterpreted by Naegele, who was approximately 15 days off when he made his calculations.
Read more about this here. (so far for evidence based medicine).
It is a well known fact that on average, primipari go to due date +6 and for a second baby the average, if left alone is dd+5 (which, strangely, was exactly when my son was born).

And then still, we're talking averages here... If you have any knowledge of statistics, this means that there will be numbers going off the average on either side, and they can be far off.There have been accounts of women carrying their babies for 52 weeks and still delivering a healthy newborn. Nature just can't be forced into statistics. They may be a good way to create an expectation, to serve as a guide, but they shouldn't be the golden standards they have become today.  Statistical approaches to pregnancy may actually be harmful for you if you just happen to be one of those moms who go off that golden average!

Variation in cycles
The calculation of a due date is based on yet another average, i.e. the female reproductory cycle based on the 28 days model and an ovulation on day 14.
Again this is an average and many, if not most women will not have a 28 day cycle.
Personally, my cycle is about 33 days... there you go with you average.
This means that if you are calculating a due date for me based on a 28 day cycle, you'll be off by 5 days, no matter the calculation you would use! Even mentioning this to your doctor will often prove no avail.
Now suppose your cycle is 28 days, this doesn't actually mean that you will ovulate on day 14. SO even if you fit the average this method of calculating is 'iffy' at best.

Image: Barchbot

Determining the gestational age with an ultrasound

Ultrasounds, when done at the right moment in pregnancy, are much better at determining the gestational age of your baby than the theoretic calculations mentioned above. Yet they are obviously still based on averages.
Also, the accuracy of an ultrasound is determined by the timeframe in which it is performed.

Given all these considerations about the due date, stripping the membranes at 41 weeks, may actually be 2 weeks earlier in your case, which means you are stripping at 39 weeks or even before that, which is considered preterm by any statistical approach.

Neonatal mortality

There is no scientific evidence to date that stripping membranes at 41 or even 42 weeks benefits neonatal outcome.
One should be aware that every medical procedure performed on a pregnant woman carries risks for the mother and the baby. Making these procedures 'standard practice' without medical indication clearly goes agains the medical rule to 'first do no harm'.

With any medical procedure, the medical necessity has to be assessed. Is the mother still fit and healthy, baby moving correctly, everything seems normal, then why bring on labor?

So what about the guidelines?

ACOG itself does not recommend interfering with a pregnancy before 42 weeks. If your doctor suggest stripping your membranes at 41 weeks, refer to this.
It is also beneficial to know your correct due date, there are ways to calculate this online, study the subject first (read the article linked to above, which also explains how to do this) and knowing the date of conception.
Be very careful when you visit the OB or midwife's office at the end of your pregnancy. Some caregivers do strip the membranes at 41 weeks as standard procedure without consent. This is illegal!



  1. Amen. I had a mw offer to strip at 38 weeks! I was actually only 37 weeks (yay for charting). I declined and went into labour on my own when baby was ready.

    1. you know, reviewing the research while writing this post, I came across a study that said: 'consecutive membrane stripping from week 38 and onward reduces the risk of going overdue'... wha? hy would you do something as barbaric for no medical reason whatsoever?

    2. Oh goodness. I just don't get it.

  2. Again, this goes hand in hand with education and making sure women know they have rights & choices. Very helpful post. Willl be sharing! (visiting from Tuesday baby link up)

    1. Completely agree, that's why we need to share share share this kind of information, so it's everywhere!

  3. Thanks for sharing this info! More women need to know all of their options. My baby girl was born two weeks "late" and I am so thankful I had a team of midwives who understood my desire to hold off all intervention. I'm so glad I was able to follow my daughter's lead and let her be born at exactly the right time for her.

    Thanks for linking up at The Tuesday Baby Link Up!


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