Many cesareans are done because the doctor diagnoses CPD which stands for cephalopelvic disproportion. This means that the pelvis is too small to birth the baby or the baby’s head is too big for the pelvis or a little of both. The problem with this diagnosis is that it is proven incorrect when the woman goes on to birth a baby vaginally, often a bigger baby. Here is a slideshow of women who had a c-section for CPD and then later had a vaginal birth. For more information on this topic, read the article Can my baby be too big for my pelvis?