Cesarean Section

Cesarean section is the most commonly performed operation in the United States. Approximately 20% of babies are delivered by cesarean section. There are many different reasons for cesarean section but the most common indications are failure to progress in labor, fetal distress, breech presentation of the fetus and a prior cesarean section.

Failure to progress in labor can have many different causes. If the baby is too big to pass through the mother’s pelvis (a condition called cephalopelvic disproportion) labor will not progress and a cesarean is indicated. If the baby’s head is slightly tilted or if the baby is facing up instead of down it may be more difficult or impossible for the baby to descend through the mother’s pelvis (think about how you would get your head through a small space…looking straight down…this is the ideal position for babies to be presenting also). Sometimes the uterus does not contract strongly enough to deliver the baby. In this instance use of the drug oxytocin (Pitocin) can help the uterus to contract adequately. If the cervix stops dilating despite a trial of adequate labor a diagnosis of failure to progress is made and a cesarean section recommended.

Fetal distress is a common term used in obstetrics. When routine fetal monitoring was introduced in the 1970’s it was hoped that it would decrease the incidence of babies born with neurological abnormalities such as cerebral palsy. Unfortunately this has not been the case. We now know that the majority of neurological injuries occur before labor even starts. Because of the imprecise nature of fetal monitoring we now use the term "non-reassuring fetal well being" as opposed to fetal distress. This means that the obstetrician, looking at the entire clinical situation and course of labor, is not sure that the baby is tolerating labor. In this case a cesarean section is often recommended.

Over 80% of babies who are in breech presentation are delivered by cesarean section in the United States. Breech presentation refers to babies who are coming through the mother’s pelvis with their feet or buttocks first. When this occurs there is an increased risk of umbilical cord prolapse and head entrapment (where the buttocks are delivered but the head is stuck in the mothers pelvis). Both of these conditions can cause serious injury to the baby. Some breech babies can be safely delivered vaginally, but the majority are delivered by cesarean section to avoid the increased risk of complications.

Probably the most controversial reason to perform a cesarean section is that of a prior cesarean section. It used to be thought that once a woman had a cesarean section she should not have a subsequent vaginal delivery for fear that the scar on the uterus would rupture. Over the past 15 years a vaginal birth after cesarean (VBAC) has become recognized as a safe alternative to repeat cesarean section in most women. Overall the success rate of VBAC is about 70% regardless of the initial reason for the cesarean section. Despite this, there are risks associated with a VBAC that should be carefully reviewed with your obstetrician. Many women request a repeat cesarean over a trial of labor partly accounting for the large number of repeat cesarean sections in the United States.

The decision to proceed with a cesarean section over a vaginal delivery is not made lightly. Although it is often said that the rate of cesarean section is "too high" no one knows what the ideal cesarean section rate is. The goal of any labor and delivery unit is to ensure that every mother and baby is delivered in the safest manner possible, be that by a cesarean or vaginal delivery.