A pregnancy that has progressed without any apparent hitch can still give way to complications during delivery. Here are some of the most common concerns.
Failure to Progress (Prolonged Labor)
A small percentage of women, mostly first-time mothers, may experience a labor that lasts too long. In this situation, both the mother and the baby are at risk for several complications including infections.
Presentation refers to the position the fetus takes as your body prepares for delivery, and it could be either vertex (head down) or breech (buttocks down). In the weeks before your due date, the fetus usually drops lower in the uterus. Ideally for labor, the baby is positioned head-down, facing the mother's back, with its chin tucked to its chest and the back of the head ready to enter the pelvis. That way, the smallest possible part of the baby's head leads the way through the cervix and into the birth canal.
Because the head is the largest and least flexible part of the baby, it's best for it to lead the way into the birth canal. That way there's little risk the body will make it through but the baby's head will get hung up. In cephalopelvic disproportion, the baby's head is often too large to fit through the mother's pelvis, either because of their relative sizes or because of poor positioning of the fetus.
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 painful "back labor," a lengthy childbirth or tearing of the birth canal. 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.
Some fetuses present with their buttocks or feet pointed down toward the birth canal (a frank, complete or incomplete/footling breech presentation). Breech presentations are normally seen far before the due date, but most babies will turn to the normal vertex (head-down) presentation as they get closer to the due date. In a frank breech, the baby's buttocks lead the way into the pelvis; the hips are flexed, the knee extended. In a complete breech, both knees and hips are flexed and the buttocks or feet may enter the birth canal first. In a footling or incomplete breech, one or both feet lead the way. A few babies lie horizontally (called transverse lie) in the uterus, which usually means the shoulder will lead the way into the birth canal rather than the head.