Belly Up

* bellies * birth * babies * breastfeeding *

Tuesday, May 3, 2011

Your Cervix is Not a Crystal Ball

When is baby coming???
 It is around mom's 38th week of pregnancy, she's just had a vaginal exam and the OB declares,"you are 2cm dilated, baby will be here soon!".  The week passes and the next week and perhaps even the next week.  Still, mom is pregnant and still 2cm...perhaps even more.


It is around mom's 40th week of pregnancy and she just had yet another vaginal exam where the OB has declared,"you are not dilated at all". 

Let me let you in on a little secret, your cervix is not a crystal ball.  It cannot predict when you will start labor.  It cannot predict if you will deliver before, after or even on your due date.  The cervix can do many wonderful things, but let's not give the cervix more credit than it is due.  A cervix cannot read the future. 

Having the cervix examined can satisfy mom's curiosity and when something is happening that can be exciting.  Obviously each bit of dilation that occurs before labor is less that must happen during labor.  However if cervical change is found, and especially if the careprovider adds the comment that labor will be soon, it can make the last weeks of pregnancy the longest of her life.  Everyday she is on high alert for impending labor and each day that it doesn't happen will be a disappointment.  Mom may now feel each discomfort of late pregnancy more acutely and her family might even travel to be in town for the big day.  However, instead of holding a baby they are all just staring at mom waiting for her to pop.  These women are often encouraged to electively induce by their due date and they agree because they are mentally exhausted from being told the baby would be here any second.

On the other hand when mom has an exam and nothing is happening, mom may start to loose confidence in her body and feel that she will be pregnant forever, or at least longer than she was hoping.  Even though it is completely normal for dilation not to occur until actual labor, these women are often made to feel that their bodies are not and will not work correctly and are pushed toward elective induction. Mom is discouraged and when the OB starts looking at induction dates, mom agrees because obviously she will not go into labor on her own any time soon and in the back of her mind she thinks her body may not even be capable of spontaneous labor.

The cervix is a a unique creature.  Some will naturally dilate prior to labor, some will not.  Some will dilate and efface slowly over time; many will only do so with the advent of contractions and a cervix that has birthed before is different than one that has not.  The bottom line is that a cervical check only tells the story of what is going on at the time of that exam.  It tells nothing about what will happen...even later that day.  A cervix does not need to reach a certain point for contractions to start, just the opposite.  Contractions will open a cervix when the time is right no matter what that cervix has been up to prior to that time.  So a mom who is closed up tight as drum is as likely to go into labor that night as the mom who is 2cm dilated and has been for a week or more.  The lucky labor winner will be the one that starts having effective contractions and that honor could go to either mom.

So why do many providers do routine vaginal exams at every appointment those last weeks of pregnancy?  I have never found a justification besides it just being a routine part of managed care. A body part cannot be "managed" if it is not assessed, measured and commented upon.  However, there is no evidenced based medical reason for routinely doing these late pregnancy exams.  In individual circumstances a vaginal exam can be helpful, but for the vast majority of women a cervix check can provide no useful or predictive clinical information and it is an uncomfortable and invasive procedure that actually carries some amount of risk. 

The good news?  You can say no thank you if you happen to be using a careprovider who does these routine vaginal exams.  If you are really curious and want to know what is happening in there, go for it, but just don't give your cervix more credit than it deserves....whatever is found means nothing about what will happen. 


  1. Wow! This was exactly what I needed to hear right now! I am 38 weeks pregnant, and at my ob appointment this week I was told that my cervix was "unfavorable" for vbac at that point and that a c-section would be in my near future if I didn't begin to dilate. Thank you! Thank you! Thank you!

  2. This is so true. At 8 days past my due date I was barely dialed to 1.5cm. I went into active labor the evening of day 9 and my sweet baby came early morning on day 10. The cervix does what it wants when it wants. :)