The Full form of CPD is Cephalopelvic Disproportion. CPD occurs when a baby’s head or body is too large to fit through the mother’s pelvis. It is believed that true CPD is rare, but many cases of “failure to progress” during labor are given a diagnosis of CPD. When an accurate diagnosis of CPD has been made, the safest type of delivery for baby and mother is a cesarean. The possible causes of CPD include: abnormal fetal positions, small pelvis, abnormally shaped pelvis, large baby due to hereditary factors, diabetes, postmaturity (still pregnant after due date has passed) and multiparity (not the first pregnancy). The diagnosis of CPD is often used when labor progress is not sufficient and medical therapy such as use of oxytocin is not successful or not attempted. CPD can rarely be diagnosed before labor begins if the mother’s pelvis is known to be small or the baby is thought to be large. Ultrasound is used in estimating fetal size but it is not totally reliable for determining fetal weight. A physical examination that measures pelvic size can often be the most accurate method for diagnosing CPD. If a true diagnosis of CPD cannot be made, oxytocin is often administered to help labor progression.