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When is a cesarean delivery necessary & what are the risks?

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A cesarean birth is the surgical delivery of an infant through incisions made in the mother’s abdomen and uterus. In the United States, one in three infants is delivered by cesarean (also known as a c-section), or more than 1 million births annually.1

A cesarean birth can be performed for many reasons2,3:

  • Multiple pregnancy. There are various reasons why a cesarean may be necessary if a woman is pregnant with twins, including labor starting too early or the fetuses not being in good position within the uterus. The chances of having a cesarean increase with the number of fetuses a woman is carrying.
  • Labor fails to progress. The cervix may not open wide enough to allow the fetus to pass into the vagina.
  • Medical concerns for the fetus. A fetus may experience an abnormal heart rate or problems with the umbilical cord.
  • Problems with the placenta (pronounced pluh-SEN-tuh). The placenta is tissue that provides nourishment to and takes away waste from the fetus.
  • A large fetus. A large fetus may present risks for vaginal delivery.
  • Breech presentation. Typically, most infants move their heads down near the birth canal by three to four weeks before the due date. If not, the buttocks, the feet, or both may be in place to come out first during birth. This is referred to as a breech presentation.
  • Maternal infections. A cesarean may protect infants from such infections as HIV or herpes.
  • A mother’s medical conditions. Certain chronic conditions such as diabetes or high blood pressure may make vaginal delivery more risky.

Can a cesarean delivery be prevented?

If the fetus is in a breech presentation, the health care provider may suggest a procedure to reorient the fetus in the womb, known as external cephalic version (ECV). To perform ECV, the health care provider places his or her hands at certain positions on the pregnant woman’s abdomen, then lifts and turns the fetus. ECV, which is typically performed at 36 weeks or later of pregnancy, increases the chances of the woman having a vaginal birth.4

Can a cesarean delivery be requested?

Some women request a cesarean birth even if a vaginal delivery is possible.5 It is important to realize that a cesarean presents increased medical risks for both the mother and her infant.

Possible risks from a cesarean birth (which are also associated with vaginal birth) include6:

  • Infection
  • Blood loss
  • Formation of blood clots in the legs, pelvic organs, or lungs
  • Injury to the bowel or bladder
  • Reaction to medication or anesthesia used

As is true for vaginal births, unless there is a medical necessity, delivery should not occur before 39 weeks of pregnancy are completed. A fetus undergoes a significant amount of development and growth in several key organ systems between the 37th and 39th weeks of pregnancy.7,8

Among women who have one cesarean delivery, more than 90% will deliver their subsequent pregnancies by cesarean.1 The more cesarean births a woman has, the greater risk there is for problems with future pregnancies, including problems with the placenta, the risk of uterine rupture, which can be life threatening for the mother and her unborn child, hemorrhage, and the need for hysterectomy (removal of the uterus) at the time of delivery.

  1. Catalano, P. M., Williams, M. A., Wise, P. H., Bianchi, D. W., & Saade, G. (2011). Scientific vision workshop on pregnancy and pregnancy outcomes (white paper). NICHD Scientific Vision Workshop on Pregnancy and Pregnancy Outcomes, Bethesda, MD. Retrieved June 18, 2012, from (PDF - 186 KB) [top]
  2. American College of Obstetricians and Gynecologists. (2011). Cesarean birth. Frequently asked questions. Retrieved June 18, 2012, from External Web Site Policy (PDF - 336 KB) [top]
  3. Eunice Kennedy Shriver National Institute of Child Health and Development. (2010). NIH consensus development conference statement on vaginal birth after cesarean: new insights. NIH Consensus and State-of-the-Science Statements, 27. Retrieved on July 25, 2012, from (PDF - 224 KB) [top]
  4. American College of Obstetricians and Gynecologists. (2011). If your baby is breech. Frequently asked questions. Retrieved July 25, 2012, from External Web Site Policy (PDF - 223 KB) [top]
  5. American College of Obstetricians and Gynecologists. (2006). Patient-requested cesarean update. Retrieved June 18, 2012, from External Web Site Policy [top]
  6. American College of Obstetricians and Gynecologists. (2011). Cesarean birth. Frequently asked questions. Retrieved online July 25, 2012, from External Web Site Policy (PDF - 336 KB) [top]
  7. National Child & Maternal Health Education Program. Focus area: late preterm birth. Retrieved August 8, 2012, from [top]
  8. Association of Women’s Health, Obstetric and Neonatal Nurses. (2012). Research-based practice project: late preterm infant initiative. Retrieved August 8, 2012, from External Web Site Policy [top]

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