© 2010, Carol Peterson, ICCE, CD(DONA) Erie, PA
Birth Journeys
Carol Peterson, ICCE, HCHI, CD(DONA)
Instilling Confidence in Birth Since 2004
814-899-7722 * cbecarol@yahoo.com * Erie, PA
Baby Too Big For Pelvis: The Truth About Cephalopelvic Disproportion, continued
How is CPD diagnosed?
The diagnosis of cephalopelvic disproportion is often used when labor does not progress after many hours. Often medical intervention enters the labor, when Pitocin is used in an attempt to cause labor to progress. Pitocin may or may not cause dilation, and in a case of CPD the baby will often still remain high in the pelvis even if dilation occurs, and pushing will not bring him further down. Often, in a case of true CPD, a baby's head will show no molding, which is a sign that the baby was not able to enter the pelvis.
CPD can rarely be diagnosed before labor begins even if the baby is thought to be large or the mom’s pelvis is known to be small. During labor, the baby’s head molds and the pelvis joints spread, creating more room for the baby to pass through the pelvis. Ultrasounds are used to estimate fetal size, however they are not 100% accurate in determining weight. While a physical examination is often used to determine pelvic size, a 2002 study showed that it is difficult to determine a woman's ability to birth without a trial of labor, even if a woman has been identified as having an odd-shaped pelvis, and even when MRIs and X-Rays are used. (1)
In many cases a diagnosis of CPD is made when there is no other explanation of why dilation does not occur, or when labor does not follow the 1 cm dilation per hour guideline.
What about future pregnancies?
Cephalopelvic disproportion is a rare occurrence. According to the American College of Nurse Midwives(ACNM), CPD occurs in 1 out of 250 pregnancies. If you have been diagnosed with CPD, this does not automatically mean that you will have this problem in future deliveries. According to a study published by the American Journal of Public Health, over 65 % of women who had been diagnosed with CPD in previous pregnancies were able to deliver vaginally in subsequent pregnancies.
If you were given a diagnosis of CPD with a prior labor, be aware that there are many causes, and it may have nothing to do with your pelvis! Perhaps your baby was in an odd position, or perhaps you were given up on too soon. Check out the video below for inspiration! (In the video you will see acronyms: CPD: cephalopelvic disproportion; VBAC: vaginal birth after cesarean; HBAC: Homebirth after cesarean; UBAC: underwater birth after cesarean.)
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Information for this article was taken from Cephalopelvic Disproportion, published by the American Pregnancy Association, www.americanpregnancy.org.
(1) MR Imaging Pelvimetry: A Useful Adjust in the Treatment of Women at Risk for Dystocia?, AJR 2002, 179:137-144