Cephalopelvic disproportion is the issue that arises when the fetus' body or head is to large to pass through the mother's pelvis.[12] Common conditions that lead to CPD are diabetes, multiple pregnancies, small or abnormally shaped pelvis, atypical fetal positions, hereditary factors, and first time pregnancies.[12] Medical professionals can usually estimate if fetal size is too large based on ultrasounds, but they are not always entirely accurate.[12] Doctors typically determine CPD when labor begins and the use of oxytocin is not effective.