In the last weeks of most pregnancies, your baby will be head-down in your uterus. A small percentage of babies assume different positions, some of which make vaginal birth risky and require surgical intervention if the baby does not turn or be turned by an obstetrician by the time you are in labor. Here are some abnormal delivery positions you should be aware of:
Rare abnormal delivery positions include face-first, brow-first, and compound, in which a hand or foot emerges from the birth canal with the head or buttocks.
Your health care provider will usually assess the position of the baby before you go into labor by feeling your uterus. A suspected abnormal position can be confirmed with ultrasound, and you and your health care provider can discuss the safest delivery options.
A few abnormal positions are more likely to occur under specific circumstances:
In some cases, a breech vaginal birth may be possible, especially in a pregnancy with multiple gestations (such as twins or triplets), although the American College of Obstetricians and Gynecologists (ACOG) recommends that breech babies be turned by external cephalic version or delivered by planned c-section. A large study found that breech babies delivered through the vagina had an increased risk of problems. This is, in part, because an infant who arrives feet- or butt-first can get his head stuck in the birth canal. The infant's body does not stretch the birth canal wide enough for the head to pass through, and the base of the baby's skull cannot compress or mold to the birth canal as it does during a headfirst passage. This can cause a prolonged labor and fetal distress. Discuss your particular situation with your doctor.
With all abnormal positions, there is additional risk to the mother and fetus. A damaged or obstructed umbilical cord may threaten the baby's oxygen supply. If the baby goes without oxygen for too long, he can develop brain damage or even die. There is also an increased risk of cervical or vaginal tears with abnormal positions.
Q: If I had a pregnancy with an abnormal position, what are the chances it will happen again?
A: If the baby was positioned abnormally because of the shape of your pelvis or your uterus, your chances of having an abnormal position in your next pregnancy are increased. In other cases, the position may have been associated with a condition such as premature labor or placenta previa and would not happen in another pregnancy unless that condition occurred again.
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