What is a Cesarean Section?

  • Previous surgery on the uterus, such as removal of fibroids from deep in the muscle wall of the upper part of the uterus, or cesarean section with a high (classical) incision.
  • Infectious conditions of the mom that could infect the baby in the birth canal -- HIV, large vaginal warts, acute herpes outbreak at the onset of labor.
  • Medical conditions of the mom that make labor too great a risk for her, such as extremely high blood pressure or severe diabetes.
  • The baby is too big for the size of the mom’s pelvis ("cephalopelvic disproportion"). Sometimes this is so obvious that a cesarean delivery is scheduled from the outset; sometimes the decision is made to do a "trial of labor" and see what happens and only resort to a cesarean delivery when the baby appears to be stuck ("failure to progress in labor").
  • More than one baby. Risks are greatly elevated, especially for the second or third baby, because the placenta may detach from the wall of the uterus before all the babies are out.
  • The exit is blocked. If a large tumor is located in the lower part of the uterus, it may block passage of the baby through the birth canal. The placenta can cover the cervix and block the exit. This is called placenta praevia.
  • The baby is breech. Even though many babies can be delivered in the breech position (bottom first), the risk of complications is greatly increased because the head and shoulders are the largest parts of a newborn. Once they have stretched the birth canal and are out the rest follows automatically. When the smaller bottom end comes out first, the head may get trapped, and the umbilical cord compressed between the baby's skull and the mom's pelvic bones. The baby then does not get any oxygen because the placental blood is cut off and the head is not yet out in the air. The American College of Obstetricians and Gynecologists now recommends that an attempt should be made to turn breech babies in late pregnancy and only deliver them by cesarean section if turning them fails.
  • The mom wants a cesarean section. A woman can choose to have a cesarean. She may choose this because she had one before and feels since she already has a scar, she does not want to subject her pelvis and vagina to the trauma of labor. Or she may just decide that labor is not for her (she may have problems to get her insurance company to pay in that case). Even with a previous cesarean women and their doctors have been pressured by the insurance companies to do a "trial of labor" (see section on VBAC). Sometimes the need for a cesarean section becomes apparent only during labor on a more or less emergency basis. In this case it is irrelevant if the baby is premature or not, as labor is already underway.

Here are some examples of when a cesarean delivery becomes medically advised once labor has started:

  • Baby problems, possible fetal distress: During labor the baby’s heart rate, including how it responds to contractions, is followed either with a monitor or by auscultation. A non-reassuring fetal heart rate pattern can be a sign that the baby is not receiving enough oxygen. This can occur because the cord is tightly wrapped around the baby’s neck or shoulder, the placenta is separating from the uterine wall, or the baby is at risk for some other reason.
  • Mom problems: Rarely, laboring women develop medical problems, such as seizures, that make it unsafe for them to continue with labor.
  • Placental problems: This usually involves the placenta beginning to separate from the uterine wall (abruption placentae). Signs of this are excessive bleeding and fetal distress.
  • Labor problems ("Failure to progress"): About 30% of cesarean deliveries are done for this reason. The most common reason the baby stops advancing down the birth canal is that the baby does not fit ("cephalo-pelvic disproportion"). If labor is allowed to continue indefinitely, something will eventually give—either the baby will develop fetal distress or the uterus will rupture.

Another reason for labor not to progress is that the contractions are not strong enough. If it is early in labor, before the membranes are ruptured, and the baby appears to be comfortable and doing well, there is nothing wrong with just waiting for a while. Usually, before going to a cesarean delivery, augmentation of labor with Pitocin will be attempted.