Medical Abbreviations: A Closer Look at CPD

The definition of cephalopelvic disproportion (CPD) is when the mother’s pelvis is not large enough to accommodate the baby's head or body for delivery. The birth passage includes the mother’s bony pelvis and soft anatomical tissues from the pelvic inlet to the outlet. Any structural variation along this area can create a situation that makes a normal vaginal delivery difficult at best. When the diagnosis of cephalopelvic disproportion(CPD) is made, the safest mode for delivery is cesarean section.

Possible causes of cephalopelvic disproportion(CPD) include:

• Large baby due to
  • Genetic predisposition
  • Diabetes
  • Post due dates
• Small pelvis
• Abnormally shaped pelvis

It is difficult to diagnosis CPD before labor begins regardless of the size of the baby or the size of the mother’s pelvis. This is because during labor the baby’s head molds and the pelvis joint spreads in order to make more room for the fetus to be able to pass through the birth canal. Sometimes a misconception is that ultrasounds can predict the ability of the fetus to be born vaginally. While ultrasounds are able to provide an estimate of fetal size, they are not able to definitely instruct healthcare providers as to the size of the infant. Physical examination is considered to be the more accurate determination as to whether vaginal delivery will be possible.

There are potential complications for both mother and child with CPD. For the mother, labor can be prolonged and premature rupture of membranes can occur from unequal contractions forces being exerted on the fetus. Some women also experience uterine rupture or tissue damage or death of the maternal soft tissues. If the membranes rupture and the fetal head is not engaged, the umbilical cord could drop below the position of the fetus and an emergent condition called cord prolapse can occur. Some infants can experience severe head trauma such as skull fractures or intracranial hemorrhage.

For more information on this topic or to request a review of a medical record with CPD, please contact our office.

Reference:

Olds, S., London, M.L., & Ladewig, P.W. Maternal Newborn Nursing: Care of the Woman with Cephalopelvic Disproportion. p.775