Complications
Fetal or newborn problems during labour and birth
If labor does not proceed normally, the fetus or newborn may have problems.
Fetal Distress:
Fetal distress is an uncommon complication of labor. It typically occurs when the fetus has not been receiving enough oxygen. The most sensitive indicator of fetal distress is an abnormal heart rate pattern in the fetus. Throughout labor, the fetus's heart rate is monitored with a fetal stethoscope—every 15 minutes during early labor and after each contraction during late labor. Or the fetus's heart rate is monitored continuously with electronic fetal heart monitoring. If a significant abnormality in the heart rate is detected, it can usually be corrected by such measures as giving the woman oxygen, increasing the amount of fluids given intravenously to the woman, and turning the woman on her left side. If these measures are not effective, the baby is delivered as quickly as possible by forceps, a vacuum extractor, or cesarean section. If the amniotic fluid appears green after the membranes have ruptured, the fetus may be in distress (but usually is not). This discoloration is caused by the fetus's first stool (fetal meconium). Fetal distress may be associated with postmaturity (when the placenta malfunctions in a postterm pregnancy) or with complications of pregnancy or labor that affect the woman and therefore also affect the fetus.
Breathing Problems: Rarely, a baby does not start to breathe at birth, even though no problems were detected before delivery. Then the baby requires resuscitation. Personnel skilled in resuscitating babies may attend the delivery for this reason.
Abnormal Position and Presentation of the Fetus: Position refers to whether the fetus is facing rearward (toward the woman's back, or face down) or forward (face up). Presentation refers to the part of the fetus's body that leads the way out through the birth canal. The most common and safest combination is head first (called a vertex or cephalic presentation) and facing down, with the face and body angled toward the right or left and with the neck bent forward, chin tucked in, and arms folded across the chest. If the fetus is in a different position or presentation, labor may be more difficult and delivery through the vagina may not be possible.
Position and Presentation of the Fetus
Toward the end of pregnancy, the fetus moves into position for delivery. Normally, the position of a fetus is facing rearward (toward the woman's back) with the face and body angled to one side and the neck flexed, and presentation is head first. An abnormal position is facing forward, and abnormal presentations include face, brow, breech, and shoulder.
When a fetus faces up (an abnormal position), the neck is often straightened rather than bent, and the head requires more space to pass through the birth canal. Delivery by forceps, a vacuum extractor, or cesarean section may be necessary.
There are several abnormal presentations. In face presentation, the neck arches back so that the face presents first. In brow presentation, the neck is moderately arched so that the brow presents first. Usually, fetuses do not stay in these presentations; they correct themselves.
Breech presentation, in which the buttocks present first, occurs in 2 to 3% of full-term deliveries. When delivered vaginally, babies that present buttocks first are more likely to be injured than those that present head first. Such injuries may occur before, during, or after birth and include death. Complications are less likely when breech presentation is detected before labor or delivery.
Sometimes the doctor can turn the fetus to present head first by pressing on the woman's abdomen before labor begins, usually at the 37th or 38th week of pregnancy. However, if labor begins and the fetus is in breech presentation, problems may occur. The passageway made by the buttocks in the birth canal may not be large enough for the head (which is wider) to pass through. In addition, when the head follows the buttocks, it cannot be molded to fit through the birth canal, as it normally is. Thus, the baby's body may be delivered and the head may be caught inside the woman. As a result, the spinal cord or other nerves may be stretched, leading to nerve damage. When the baby's navel is first seen outside the woman, the umbilical cord is compressed between the baby's head and the birth canal, so that very little oxygen can reach the baby. Brain damage due to lack of oxygen is more common among babies presenting buttocks first than among those presenting head first. In a first delivery, these problems are worse because the woman's tissues have not been stretched by previous deliveries. Because the baby could be injured or die, delivery by cesarean section is preferred when the fetus is in breech presentation.
Occasionally, a fetus lying horizontally across the birth canal presents shoulder first. A cesarean section is performed, unless the fetus is the second in a set of twins. In such a case, the fetus may be turned to be delivered through the vagina.
Multiple Births: The number of twin, triplet, and other multiple births has been increasing during the last two decades. During pregnancy, the number of fetuses can be confirmed by ultrasonography.
Carrying more than one fetus overstretches the uterus, and an overstretched uterus tends to start contracting before the pregnancy reaches full term. As a result, the babies are usually born prematurely and are small. In some cases, the overstretched uterus does not contract well after delivery, causing bleeding in the woman after delivery. Because the fetuses can be in various positions and presentations, vaginal delivery can be complicated. Also, the contraction of the uterus after delivery of the first baby may shear away the placenta of the remaining baby or babies. As a result, the baby or babies that follow the first may have more problems during delivery and later.
For these reasons, doctors may decide in advance how to deliver twins: vaginally or by cesarean section.
Occasionally, the first twin is delivered vaginally, but a cesarean section is considered safer for the second twin. For triplets and other multiple births, doctors usually perform a cesarean section.
Shoulder Dystocia: Shoulder dystocia occurs when one shoulder of the fetus lodges against the woman's pubic bone, and the baby is therefore caught in the birth canal. The head comes out, but it is pulled back tightly against the vaginal opening. The baby cannot breathe because the chest is compressed by the birth canal. As a result, oxygen levels in the baby's blood decrease. This complication is more common with large fetuses, particularly when labor has been difficult or when forceps or a vacuum extractor has been used because the fetus's head has not fully descended in the pelvis.
When this complication occurs, the doctor quickly tries various techniques to free the shoulder so that the baby can be delivered vaginally. In extreme circumstances, if the techniques are unsuccessful, the baby may be pushed back into the vagina and delivered by cesarean section.
Prolapsed Umbilical Cord: The umbilical cord precedes the baby through the vagina (prolapses) in about 1 of 1,000 deliveries. When the umbilical cord prolapses, it may constrict so that the fetus's blood supply is cut off. This complication may be obvious (overt) or not (occult).
Prolapse is overt when the membranes have ruptured and the umbilical cord protrudes into or out of the vagina before the baby emerges. Overt prolapse usually occurs when a baby emerges buttocks first (breech presentation). But it can occur when the baby emerges head first, particularly if the membranes rupture prematurely or the fetus has not descended into the woman's pelvis. If the fetus has not descended, the rush of fluid as the membranes rupture can carry the cord out ahead of the fetus. If the cord prolapses, immediate delivery, almost always by cesarean section, is necessary to prevent the blood supply to the fetus from being cut off. Until surgery begins, a nurse or doctor holds the fetus's body off the cord so that the blood supply through the prolapsed cord is not cut off.
In occult prolapse, the membranes are intact and the cord is in front of the fetus or trapped in front of the fetus's shoulder. Usually, occult prolapse can be identified by an abnormal pattern in the fetus's heart rate. Changing the woman's position or raising the fetus's head to relieve pressure on the cord usually corrects the problem. Occasionally, a cesarean section is necessary.
Nuchal Cord: The umbilical cord is wrapped around the fetus's neck in about one fourth of deliveries. Normally, the baby is not harmed. Before birth, a nuchal cord can sometimes be detected by ultrasonography, but no action is required. Doctors routinely check for it as they deliver the baby. If they feel it, they can slip the cord over the baby's head.
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