A breech presentation is a birth delivery position in which a baby enters the birth canal feet or buttocks first, opposed to the head down or “vertex” presentation. The frank breech position is the most common of the four types of breech presentations. In frank breech, the baby’s rear end is aimed toward the mother’s cervix, with legs extended at the knees and the feet placed on either side of the head. The frank breech position is present in 65-70% of all breech births.
In more than 50% of breech births, there is no evident cause for the failure of the baby to position in the normal head-down presentation. In the remaining cases, there are specific factors that encourage frank breech and other breech positions. Prematurity is the primary cause of breech births. Abnormal amniotic fluid volume, history of premature birth, and prior Cesarean section delivery are other common causes for breech positioning.
Based on symptoms alone, it is difficult to determine if a baby is in frank breech position. Most breech presentations do not feel out of the ordinary to the mother. Women who are more than 36 weeks pregnant and experience pressure or kicking in the lower abdomen should visit a physician for an examination, however. During this visit, the physician can examine your cervix, and feel the upper and lower abdomen to ascertain the positioning. A conclusive diagnosis of frank breech presentation requires a fetal ultrasound.
Normally, as a baby increases in size, a head-down presentation will be naturally achieved. At 32 weeks gestation, nearly 25% of babies are in the breech position. This number decreases to 3% at term. If a woman is near full term, and the baby remains in frank breech position, a midwife or physician can attempt to turn the baby by manually manipulating the uterus. This procedure is known as external cephalic version or ECV. Many times this technique is successful. In other cases, the baby may be too large to move, or may turn back into the breech position.
Approximately 30-50% of breech babies are delivered vaginally. In frank breech presentation, vaginal birth is favored. The deciding factors for delivery method depend on the estimated weight of the baby and the experience of the midwife or doctor. Fetal monitoring will be used throughout the labor process if a vaginal delivery is attempted. If the baby displays any signs of distress, a Cesarean section will be given consideration.