Thursday, June 17, 2010

What is a cesarean section?


Indications and Procedures


Cesarean section was initially intended to be performed when it is impossible or dangerous to deliver
a baby vaginally. For example, the operation is necessary if the fetus is unable to fit through the mother’s pelvis or if it shows signs of fetal distress. Fetal distress is detected by abnormal changes in the fetal heart rate, which may indicate that the fetus is not receiving adequate oxygen from the placenta. Other reasons for the procedure include a placenta that is lying over the cervix, which blocks the opening to the birth canal (placenta previa); scarring of the uterus from other surgical procedures (or previous cesarean section), which reduces the ability of the uterus to contract; unsuccessful induction of labor with oxytocin (Pitocin); breech
presentation, in which any part other than the head presents first; and postmaturity, in which gestation and fetal development indicate that labor should have begun yet is delayed.



These medically necessary indications for a cesarean section have been largely overshadowed by a tremendous increase in cesareans because of patient choice and/or by an overuse of the practice by physicians for a variety of reasons, including over-medicalization of birth, support of often misinformed patient choice, or convenience. In 2010, more than 32 percent of live births were delivered by cesarean. One major reason for this increase is that after a woman has a cesarean, vaginal delivery in subsequent births becomes less likely.


A cesarean section allows the delivery of a baby through a horizontal or vertical incision through the mother’s abdominal and uterine walls. Prior to surgery, an anesthesiologist gives the mother an epidural or spinal anesthetic so that she can remain conscious but free of pain during the procedure. Occasionally, under certain emergency conditions such as severe fetal distress, a general anesthetic is given. The use of epidural anesthesia

, however, is preferred in the majority of deliveries. The anesthesiologist administers epidural anesthesia by injecting a locally acting anesthetic into the space that surrounds the spinal cord. This space is known as the epidural space, and when it is filled with anesthetic agents, the nerves to the abdominal and pelvic cavities are blocked.


A catheter is inserted into the urinary bladder to empty it prior to making an incision into the abdomen. Typically, a horizontal incision is made just above the pubic bone, as this type of cut heals more readily and is more cosmetically acceptable. Once the pregnant uterus is exposed, a second transverse incision is made in the lower region of the uterus. The amniotic fluid is drained off by suction, and the baby is delivered. Once the infant’s head is exposed, its mouth and nose are cleared of any fluid that may hinder respiration. After completely removing the baby from the uterine cavity, the physician clamps the umbilical cord, cuts and ties it, and hands the baby to the parents or a member of the surgical team. Vertical incisions are more likely to be made in emergency situations, since they allow for quicker delivery; however, they result in poorer healing of the uterine muscle. After the placenta is delivered, the physician sutures the uterine and abdominal walls and provides postoperative care to the patient. A
drug known as ergonovine can be used after delivery of the infant to stimulate uterine contractions and to aid in preventing postpartum bleeding. A patient in pain or discomfort may be given analgesics such as meperidine or morphine as needed. The medical staff closely monitors the patient’s vital signs, such as her heart rate, blood pressure, and urine flow, as well as the status of the uterus, including abnormal bleeding.




Uses and Complications

The major adverse effects to women undergoing cesarean section have been complications caused by anesthesia, infection, hemorrhaging, and blood-clotting disorders, such as thromboembolic episodes in which a blood clot breaks loose from a vessel and causes a stroke, heart attack, or pulmonary
embolism. One of the most frequent complications from cesarean section is postoperative fever. Physicians can reduce the incidence of fever, however, by administering antibiotics prophylactically. Some women also experience damage to internal organs during the surgery, especially the bowel and bladder. Risks to the fetus include entrapment of a fetal head or limb in the uterine incision, which may result in injury to the head or spine and in limb fractures, and wounding of the fetus when the incision is made in the uterine wall.


Patients and their health care providers must weigh these potential adverse effects against the benefits of cesarean sections. Cesarean section is often performed when a normal vaginal delivery is possible, and women may not be fully aware of the risks involved. For most patients who are failing to progress in labor or whose baby is in the breech position or in distress, a cesarean is indicated. It is not always necessary, however, for a cesarean to be performed on a patient who has had a previous cesarean. Research supports the use of attempted vaginal births after cesarean (VBACs) for women who are appropriately selected, counseled, and managed.




Perspective and Prospects

Cesarean section was first performed in ancient Rome when the law required physicians to examine the fetus in the event of a mother’s death. Some medical historians have proposed that Julius Caesar was delivered in this way; the term for the procedure is derived from his name. Whether this story is truth or legend, however, is still a matter of debate. In the eighteenth century, many women attempted to perform the procedure as a method of abortion. These self-surgeries usually resulted in the mother’s death.


The rate for delivery by cesarean section has increased in the United States since the 1960s. In 1965, 4.5 percent of babies were born via cesarean. By 2010, more than 32 percent of all children born in the United States were delivered by cesarean. The cesarean delivery rate declined during the late 1980s through the mid-1990s but has been on the rise since 1996. Because fetal monitoring during labor is much more sophisticated than it was in the past, problems with the fetus are more easily detected, leading to an increased number of cesareans; still, far too many cesareans are being performed for reasons other than medical necessity. There is a great deal of controversy currently about the practice of cesarean delivery on maternal request (CDMR), and about whether women are adequately informed of the risks of the procedure.




Bibliography


Crombleholme, William R. “Obstetrics.” In Current Medical Diagnosis and Treatment 2006, edited by Lawrence M. Tierney, Jr., Stephen J. McPhee, and Maxine A. Papadakis. New York: McGraw-Hill Medical, 2006.



"Cesarean Birth." acog.org, June 18, 2013.




Cesarean Section: Understanding and Celebrating Your Baby’s Birth. Baltimore: Johns Hopkins University Press, 2003.



Cunningham, F. Gary, et al., eds. Williams Obstetrics. 23d ed. New York: McGraw-Hill, 2010.



Greene, R. A., C. Fitzpatrick, and M. J. Turner. “What Are the Maternal Implications of a Classical Caesarian Section?” Journal of Obstetrics and Gynaecology 18, no. 4 (July, 1998): 345–347.



Menacker, F., E. Declercq, and M. F. Macdorman. “Cesarean Delivery: Background, Trends, and Epidemiology.” Seminars in Perinatology 30, no. 5 (2006): 235–241.



Menaker, F. "Neonatal Mortality Risk for Repeat Cesarean Compared to Vaginal Birth afterCesarean (VBAC) Deliveries in the United States, 1998–2002 Birth Cohorts." Maternal & Child Health Journal. 14,2. (March 2000): 147–154.



Murphy, Magnus. Choosing Cesarean: A Natural Birth Plan. Amherst, New York: Prometheus Books, 2012.



Tower, Clare L., B. K. Strachan, and P. N. Baker. “Long-Term Implications of Caesarean Section.” Journal of Obstetrics and Gynaecology 20, no. 4 (July, 2000): 365.

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