Breech Babies-continued

Although the risks associated with vaginal delivery from the breech presentation are much higher than the risk of delivery head first, many breech babies do well when delivered vaginally. In recent years, there has been a small but growing number of women who have decided to forego C-section and attempt vaginal delivery. Years of experience before C-sections became routine helped to identify those types of breech positions that are at highest risk. This information can help parents make a more informed decision.

There are three types of breech presentation. The difference among the types is the position of the baby's legs relative to the rest of the body. Frank breech, in which the baby's legs are folded up against its body, is the most common type. The entire breech usually fills the pelvis and the baby's relatively compact position makes a vaginal delivery more likely. The frank breech presentation is the safest for vaginal delivery.

Even if the baby is in the frank breech presentation, however, there are a number of other criteria it should meet before proceeding with a vaginal delivery. Ultrasound examination should show that the baby is not unusually large and that the head is flexed (tilted forward). Entrapment of the head is more likely for babies who are unusually large or whose heads are not flexed.

If the decision is made to attempt breech vaginal delivery, close monitoring and careful observation of the progress of labor is mandatory. Any indication that the baby is too large to fit, such as slow progress in labor, should be regarded as a signal that C-section is the safer course. This is because the body is smaller than the head. If the body is having difficulty fitting through the pelvis, the head will never fit, especially because there is no time for it to undergo molding, as it would if it were passing through the pelvis head first. If labor progresses smoothly, successful vaginal delivery is more likely. As in normal labor, the cervix dilates to 10 cm. Then the breech baby must be pushed out.

In the frank breech presentation, the buttocks are born first. The body is allowed to slide out with the obstetrician's support. After the abdomen is out, the obstetrician gently rotates the baby to either side, in preparation for delivery of the arms. This ensures that the arms are free and not accidentally trapped behind the baby's head. After the arms are born, the shoulders follow.

Now it is time for the head to be born. The delivery of the head can be assisted by a variety of maneuvers, all of which attempt to keep the head flexed as it is gently delivered. This is the most critical part of the delivery, because the possibility always remains that the head could become trapped behind the pubic bone. In difficult cases, special forceps may be required to deliver the head. Once the head has been delivered, everyone breathes a big sigh of relief. The cord is clamped and cut and the baby is thoroughly examined to make sure that no injuries have occurred.

Other breech presentations are not considered safe to attempt vaginal delivery. In the complete breech, the baby looks as if it is sitting Indian style, with its legs crossed in front of it. As you might imagine, it is difficult, if not impossible, for the baby to pass through the pelvis in this position.

A footling breech has one leg (single footling breech) or both legs (double footling breech) underneath it. The feet lead the way in passing through the pelvis. Although the feet fit easily, their small size creates another problem. As the cervix dilates, the umbilical cord may fall down around the baby's feet. When the membranes rupture, the cord may fall out of the uterus altogether (this is known as cord prolapse). This is an emergency. When the cord falls out of the warm, wet environment of the uterus into the vagina it may go into spasm, completely cutting off the flow of blood and depriving the baby of oxygen. Emergency C-section is required to deliver the baby as soon as possible. Cord prolapse is a fairly common complication of labor in single or double footling breech babies.

Women contemplating vaginal breech delivery are advised that only the frank breech presentation is safe. The complete breech or the footling breech should be delivered by C-section. It is important to remember, however, that even if the baby is in the frank breech presentation, and all the other criteria for vaginal delivery are met, there is still a significantly higher risk of injury to the baby by vaginal delivery than by head-first delivery or by C-section.