Monday, July 9, 2012

Ask an OB: Why do docs induce when women are overdue?

"Ask an OB" is a weekly series with Dr. Maude "Molly" Guerin, MC, FACOG.  If you have a question you'd like to ask her, please share it with us here.

Why do doctors get nervous and want to induce women when they are overdue?  Doesn’t Mother Nature know when the best time is? ~ Lansing mom

Most of the time she does. My three boys were 14, 12, and 10 days overdue – I had no nonstress tests, no ultrasounds, no discussion of induction, even though my blood pressure was high – and everyone lived!  My how times have changed in the last 30 years. The problem is that stillbirth does become more common as pregnancy advances, dramatically after 42 weeks – it’s 17 times higher after 42 weeks than it is at your due date. That being said, the chances are good that your baby will be fine even at 42 weeks – look at these numbers:

Completed Weeks
Stillbirth/10,000 births
Obstetrics&Gynecology, VOL. 103, NO. 1, JANUARY 2004

So in today’s world we like to get people delivered before 42 weeks. Usually once you pass your due date we are checking the amniotic fluid by doing a quick ultrasound once a week – this helps us know the placenta is still working well. Also doing a nonstress test by putting you on the monitor for 20 minutes twice a week helps us know the baby is doing well. These tests are not perfect, and our data on them is always being updated, but currently they are the standard of care and recommended by the American College of Obstetrics and Gynecology.

Here is a meta-analysis of studies on the management of post-dates pregnancy by the highly respected Cochrane Group:

The Cochrane Pregnancy and Childbirth Group trials register was searched.
Selection criteria
Randomised and quasi-randomised trials of interventions involving the intention to induce labour at a specified gestational age.
Main results
Twenty-six trials of variable quality were included. There were four trials of routine early pregnancy ultrasound, two of nipple stimulation, nineteen of routine versus selective induction of labour and one of antenatal fetal monitoring. Routine early pregnancy ultrasound reduced the incidence of post-term pregnancy (odds ratio 0.68, 95% confidence interval 0.57 to 0.82). Breast and nipple stimulation at term did not affect the incidence of post-term pregnancy (odds ratio 0.52, 95% confidence interval 0.28 to 0.96). Routine induction of labour reduced perinatal mortality (odds ratio 0.20, 95% confidence interval 0.06 to 0.70). This benefit is due to the effect of induction of labour after 41 weeks. Routine induction of labour had no effect on caesarean section.

In other words, induction of labor after 41 weeks reduced the chances of the baby dying by 80%. And since we never know if your baby is going to be one of the 9966 out of 10,000 who is fine, or be one of the 34 that is not – we want to get you delivered.


  1. Hi Dr. Guerin, thanks for sharing your viewpoint with us! I was wondering if you'd read the Cochrane review all the way through. When I did, I was surprised to find that the majority of these studies were done more than 20 years ago—between 1969 and 1992. Furthermore, many of these studies were conducted in India and Thailand. In the 7 studies that were conducted more recently (after 1992), there was only 1 stillbirth at all (in the watchful waiting group) reported out of 1817 women. It surprises me that OBs quote this Cochrane review all the time to pressure women into inductions, when the quality of the evidence is not as high as you might think it is. A mom’s overall risk of having anything go wrong with “watchful waiting” is EXTREMELY remote (even the Cochrane reviewers admit this in their conclusions). I have heard that “standard of care” in my community is induction by 41 weeks, sometimes even before. That being said, would you support a woman if she wanted to go until 42 weeks +/- a few days? What would you do if she refused an induction?

  2. Sorry! I didn't intend for the comment above to be an anonymous post. My name is Rebecca from

  3. Hello Rebecca: yes, sorry if I did not make it clear that the chance of anything bad happening is small - yes it is VERY small! The data in the table shows that perinatal death is only 34 per 10,000 births at 42 weeks. (This is not the Cochrane database, just a community hospital's experience with 45,000 births over 10 years - but it does agree with the Cochrane review). But telling patients the "chance for anything bad happening is small so we should wait" or "the chance of your baby dying is 4 times higher next week so we should induce" is not the same as telling patients what the numbers are. I am in favor of giving women actual data and letting them decide. Women are smart, women know what their risk tolerance is, and women are capable of making these complex decisions when they are given all the facts. This would include the fact that if you have no prior vaginal delivery and you are induced before your cervix is ready your chance for a C section is DOUBLED compared to waiting for spontaneous labor.
    So thank you for sharpening our focus here - I am not advocating waiting till 42 weeks nor routine induction at 41 weeks. I am advocating giving women information and letting them decide. My PERSONAL thought is that a C section is better than a stillbirth, so IF patients want my personal opinion, I would recommend induction at about 41 weeks. And yes, I have had many many patients that have listened to my opinion and politely declined that advice - and I make sure to let patients know that I am fine with that! People don't do what I say every day and I love those people. Be spunky, be thoughtful, be collaborative, listen, and be heard. That's all I ask - then do what you think is best.

  4. Love your response! Thank you so much! ~Rebecca