Pregnancy Problems

Cephalopelvic Disproportion (CPD)

Worried baby will be too big for a vaginal birth. We've got the details on just how common CPD is — and how to know if you've got it. Plus, everything you want to know if you do.

What is cephalopelvic disproportion (CPD)?

Don’t let the medical speak intimidate you: Cephalo (head) pelvic (pelvis) disproportion (one’s too big for the other) is just Latin for “there’s no way the baby’s going to fit down there” for delivery. Doctors also use this as a general term for a lack of progress in labor (your cervix isn’t dilating, or the head isn’t descending).

Are there any tests for CPD?

A good old-fashioned physical exam measuring the size of your pelvis and also an ultrasound can help estimate your baby’s size before you go into labor, but neither is 100 percent accurate. In the end, it’s difficult to predict the condition before labor starts, since your body can change in some amazing ways once the birthing process begins. Plus, there’s no good way to know how the head and pelvis will actually match up. (Don’t worry — if your baby is very large, say, over 10.5 pounds, your doctor may order a c-section anyhow.)

How common is CPD?

It’s rare. True CPD occurs in about 1 out of 250 pregnancies and requires cesarean delivery. Luckily, even if you’ve been diagnosed with CPD, that doesn’t mean all your future deliveries will be under the knife: Research shows more than 65 percent of women who had CPD in a previous pregnancy were able to have a vaginal delivery the next time around.

How did I get CPD?

It might just be biology. Maybe you just happen to have a somewhat narrow or small pelvis and your baby has a larger-than-average-size head.

How will CPD affect my baby?

Most likely, she’ll simply be delivered via c-section. There’s no evidence to indicate that CPD will affect your baby in any other way after birth.

Next page: Prevention, treatments and more resources for CPD

What can I do to prevent CPD?

There’s not much in the way of prevention for CPD, since it comes down to a matter of your shape and your baby’s size, and how the two match up when delivery starts to happen.

What do other pregnant moms do when they have CPD?
 
“My OB told me that my pelvis was too small (aka cephalopelvic disproportion) and basically that I shouldn’t even bother with a vaginal birth after cesarean attempt. But I’ve done a lot of research since then, and I’ve discovered that when CPD is the reason for the primary cesarean, more than 60 percent of women are able to have successful VBACs.”

“In recovery, they told me I had something called cephalopelvic disproportion, which means either the baby is too big to pass through your pelvis, or your pelvis is too small for the baby to pass through it. The doctor said that since my LO was a rather small baby, I had the latter, and it was unlikely that I would ever be able to have a vaginal birth.”

“My mother was in labor with her first child for 10 hours, and the doctor realized then that the baby was too big to deliver vaginally...he later discussed with her that she had CPD. My sister gave birth just about a year ago and opted for a c-section based on the size of her baby and the fact that she has a narrow pelvis, just like my mother.”

Are there any other resources for CPD?

American Pregnancy Association

Plus, more from The Bump:

Will my baby be too big for a vaginal delivery?

What happens in a c-section?

What will the c-section scar look like?

By Christian Hoffman, MD, medical director and chair of the department of obstetrics/gynecology at Robert Wood Johnson University Hospital Hamilton in Hamilton, New Jersey