Elective Cesarean Section. Part 2: The Baby. - All About Epidural
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Elective Cesarean Section. Part 2: The Baby.

Date: February 16th, 2015

Benefits

No randomized trials on request cesarean presently exist, and the data on its risks and benefits outcomes has been extrapolated from other, less methodologically reliable studies. One of the large sources of data is The Term Breech Trial, an international multicenter trial published in 2000 that included 2088 women with their babies in breech position. The study was randomized and found that for breech pregnancies babies did better in cesarean group. The death rate and the rate of serious complications among babies was 1.6% in the cesarean group and 5.0% in the planned vaginal delivery group. Short-term complications among the mothers were similar. It is important to remember that breech pregnancies carry considerably higher risk, and the results from this trial cannot be directly extrapolated to normal pregnancies. Still, the results point at the significant protective potential of the cesarean section.

One of the largest published analyses preformed by the researchers from the Texas University has looked into four significant complications among the newborns: shoulder dystocia, fetal trauma, neonatal encephalopathy and intrauterine fetal demise and the effect of elective cesarean section at 39 weeks gestation. What they found is as follows.

Shoulder Dystocia

Shoulder dystocia is a serious complication of labor is when, after the head of the newborn is delivered, the shoulder cannot pass through the birth canal. The maneuvers that are used to deliver the shoulders can lead to the damage of the nerves (brachial plexus) passing in the shoulder region and the subsequent paralysis of the arm. In more severe cases, the umbilical cord can become compressed between the baby’s body and the vaginal wall. In this scenario blood supply to the baby is cut off and the baby can die.

The risk of brachial plexus injury during vaginal birth varies between 0.047 and 0.6%. Approximately 15% of those will result in permanent damage. The most conservative estimates indicate that 3 million vaginal deliveries – approximate number of vaginal deliveries a year in USA – would result in 675 cases of permanent brachial plexus injury every year. Cesarean section would eliminate vast majority of these cases.

Birth Trauma

Birth trauma refers to physical injuries resulting from the mechanical stress of childbirth. Examples of such trauma include the spinal cord injury, fractures of the spine or extremities, rupture of the spleen or liver and others. The incidence of severe birth trauma varies between 0.2 and 2 in 1000 births. The risk of this complication is higher when forceps and/or vacuum are used, as well for larger infants and shorter mothers. Trauma to the newborn can also occur with cesarean section, but it is much more likely with abnormal position of the fetus, premature infants or in the setting of emergency cesarean. In contrast, the risk of fetal trauma during elective cesarean section it is an order of magnitude less than occurs with vaginal delivery and almost unheard of with elective cesarean delivery with normal presentation of the baby at term.

Neonatal Encephalopathy and Permanent Neurologic Injury

Encephalopathy is the proper term for brain damage. The International Consensus Conference concluded in 1999 that in 90% of cases of cerebral palsy are not caused by the adverse events during labor. However, the study from Western Australia in 1998 demonstrated that elective cesarean section reduced risk of encephalopathy by 83%. If this result is extrapolated to the American population elective cesarean section could reduce the number of cases of neonatal encephalopathy every year from 11,400 to 1900.

Another study analyzed the outcomes in 30,000 women with the previous cesarean. Among  women who were given the trial of vaginal birth the incidence of encephalopathy was 0.0782%. By comparison, those who had an elective repeat cesarean delivery had no cases of neonatal encephalopathy. Extrapolation of these data to the 3 million women annually in the United States shows that 2347 cases of hypoxic ischemic encephalopathy would be eliminated.

Intrauterine Fetal Death

In the United States, stillbirth occurs in almost 1% (7 per 1000) of all births, and in the year 2000, there were nearly 27,000 stillbirths. The percentage of fetal deaths is fairly consistent throughout pregnancy. However, several investigators reported significant increase in fetal deaths in late pregnancy, from 36 – 37 weeks onwards. It is without dispute that elective cesarean section at 37 and more weeks would nearly eliminate all fetal death that happen due to adverse conditions in labor, while the risk of complications related to the prematurity of the newborns would be low. It has been estimated that elective cesarean section at 39 weeks could prevent between 1500 and 6000 of fetal deaths annually in USA.

Complications

The most concerning impact on the neonate from elective cesarean appears to be the risk of respiratory complications related to prematurity. In order to be able to breathe the lungs of the baby need to be sufficiently mature. It is also believed that the passage of the baby through the birth canal triggers the release of hormones – corticosteroids and catecholamines – that facilitate the transition to breathing air.

There are two main respiratory complications attributable to immaturity: Transient Tachypnea of the Newborn (TTN) and Respiratory Distress Syndrome (RDS) also called Hyaline Membrane Disease. TTN develops because of the fluid that remains in the baby’s lungs after birth. It is a benign condition and represents about 40% of all respiratory complications in the newborns. It manifests as rapid breathing that develops immediately or within two hours of birth. The symptoms may last from a few hours to two days.

RDS occurs due to prematurity of the lungs. The pathology of this condition is complex, but in short immature lungs are not capable of transferring adequate amount of oxygen from the atmosphere to the baby’s blood during breathing. The babies with RDS are distressed and visibly struggle to breathe. In serious cases mechanical ventilation of the lungs in the intensive care unit may be necessary.

A study from the UK prospectively collected data on over 33 000 deliveries at later than 37 weeks of gestation over 9 years and found that the respiratory complications were more three times higher for babies delivered by cesarean compared with cesarean during labor, and about six times higher than in those who were delivered vaginally. The risk of complications was decreasing with increasing gestational age. The authors concluded that neonatal respiratory complications could be significantly reduced if elective caesarean section was performed after 39 week of pregnancy.

A more recent study from Italy found similar increase in the risk of respiratory complications among newborns with elective cesarean. However, after 39 weeks of pregnancy the risk was similar between cesarean and vaginal delivery groups.

Though generally respiratory complications are benign and require limited intervention, some of these newborns become seriously ill and may need prolonged oxygen therapy, mechanical ventilation and other sophisticated treatments. Death may occur, however because most statistics regarding RDS are derived from premature babies, it cannot be directly extrapolated to RDS that follows elective cesarean.

At least one study suggests that the risk of RDS after elective cesarean can be reduced by corticosteroids. 998 patients were randomized to receive steroid betamethasone or no medication prior to elective cesarean at term. The risk of RDS was reduced by half in the steroid group. However, at this time steroids are not routinely recommended prior to elective cesarean section.

The Verdict

As far as babies are concerned, immediate benefits of elective cesarean are apparent. Serious complications among newborns are rare, and that’s why in absolute numbers the reduction in risks does not look dramatic. Yet, when they occur, the consequences of these complications are severe. Clinical data unequivocally demonstrates that shoulder dystocia, birth trauma, neonatal encephalopathy and intrauterine death are significantly reduced by elective cesarean section.

The most common neonatal problem in elective cesarean section respiratory. While benign and self-limiting in most babies, it may require admission to the intensive care unit and, in some cases, artificial ventilation of the lungs. This complication is the result of immaturity of the lungs, and therefore it is very important to get the gestational age of the baby right. If the cesarean is performed at 39 weeks or later the risk of respiratory distress is equal to that of the babies born by spontaneous labor.

Photo from: http://www.freedigitalphotos.net/images/newborn-photo-p268110

Dr. Eugene Smetannikov is a practicing anesthesiologist with the interest in obstetric anesthesia. He is the author of the most comprehensive book on the subject, The Truth About Labor Epidural

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