Understanding Labor and Delivery Complications -- the Basics
What Are Common Labor and Delivery Complications? continued...
Other presentations are:
Frank breech. In a frank breech, the baby's buttocks lead the way into the pelvis; the hips are flexed, the knees extended.
Complete breech. In a complete breech, both knees and hips are flexed, and the baby's buttocks or feet may enter the birth canal first.
Incomplete breech. In an incomplete or footling breech, one or both feet lead the way.
Transverse lie. A few babies lie horizontally in the uterus, called a transverse lie, which usually means the baby's shoulder will lead the way into the birth canal rather than the head.
In cephalopelvic disproportion, the baby's head is too large to fit through the mother's pelvis, either because of the size or because of the baby's poor positioning. Sometimes the baby is not facing the mother's back, but instead is turned toward her abdomen (occiput or cephalic posterior). This increases the chance of a lengthy, painful, childbirth, often called "back labor," or tearing of the birth canal.
In malpresentation, the baby is not "presenting" or positioned in the normal way. In malpresentation of the head, the baby's head is positioned wrong, with the forehead, top of the head, or face entering the birth canal, instead of the back of its head. Sometimes a placenta previa (when the placenta blocks the cervix) may cause an abnormal presentation. But many times the cause is not known.
Abnormal presentations increase a woman's risk for uterine or birth canal injuries and abnormal labor. Breech babies are at an increased risk of injury and a prolapsed umbilical cord, which cuts off the baby's blood supply. A transverse lie is the most serious abnormal presentation, and it can lead to injury of the uterus, as well as injury to the fetus.
Your doctor will determine the presentation and position of the fetus with a physical exam. Sometimes a sonogram helps in determining the position of the fetus. When a baby is in the breech position before the last six to eight weeks of pregnancy, the odds are still good that the baby will change position before birth. But the bigger the baby gets, and the closer you get to your due date, the less room there is in the uterus for the baby to turn. Doctors estimate that about 90% of fetuses who are in a breech presentation before 28 weeks will have turned by 37 weeks, while over 90% of babies who are breech after 37 weeks will most likely stay that way.