Cephalodisproportion (CPD)


What is cephalopelvic disproportion (CPD)?

CPD is a medical term whereby a baby’s head or body is too large to fit the mother’s pelvis.
Why does this happen?
  • Large baby
  • The baby’s head is large e.g hydrocephalus (a fetal abnormality where there is fluid accumulation in the baby’s brain)
  • Small pelvis  e.g in small stature woman
  • Abnormal pelvis in the mother e.g bony deformity such as rickets or an abnormally shaped pelvis.
  • Abnormal position of the baby’s head during labour e.g OP position where the baby’s face is facing mother’s front instead back, head tilted to the side
How is the diagnosis CPD being made?
The diagnosis of CPD is more accurately being made during labour as during labour the baby’s head will mould and the pelvic joints will spread to allow the baby to pass through the pelvis.  The diagnosis of CPD could be made if the baby’s head does not descend down through the pelvis despite adequate uterine contraction often aided by oxytocin and sufficient time is given for labour to progress. If you have been diagnosed with CPD previously, pelvimetry may be done by your doctor. Pelvimetry assessment could be either clinically (pelvic examination) or radiologically (x-ray, MRI or CT scan). Unfortunately, pelvimetry is not a reliable assessment tool to diagnose CPD.
How common is CPD?
CPD is a rare occurrence 1 out of 250 pregnancies.
If I had a diagnosis of CPD for my previous caesarean section, is it possible for me to still have a vaginal delivery in future?
This issue should be discussed with your own doctor. If you have been diagnosed with CPD in your previous pregnancy does not automatically means that you could not have a vaginal delivery in future.

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