Risks of Difficult Labor Health Article

Babies in breech presentation have increased risks for a number of complications. Some of these complications are directly or partially due to the breech presentation itself, while others are merely associated with the breech presentation.

Complications directly attributable to the baby being in a breech presentation include:

• poor oxygen delivery to the baby during vaginal delivery due to umbilical cord compression; and
• neurological damage to the baby during vaginal delivery, either from cord compression or maneuvers required to deliver the baby vaginally.

Overall, these complications are more common in breech babies than those that present cephalically (head-first). In turn, these complications may arise from:

• the umbilical cord slipping through the cervix, leading to cord compression;
• the baby's head being trapped by the cervix during vaginal delivery since it is the last part to be delivered instead of the first; or
• damage to the spinal cord or arms during vaginal delivery.

The umbilical cord may slip into the cervix during labor or rupture of the fetal membranes, especially when the fetus is in an incomplete breech presentation. When this happens, constriction of the cord may limit the supply of blood and oxygen to the baby, possibly causing damage to the brain and other organs.

Those complications associated with but not directly due to breech presentation include:

• Increased Risk of Birth Defects: Approximately 6 to 7% of babies in breech presentation at the onset of labor have major birth defects, compared to only 2 to 3% in cephalic presentations. Most experts believe that birth defects actually lead the fetus to assume or stay in a breech presentation. For example, fetuses with anencephaly, a very serious defect in the formation of the central nervous system are often breech at the onset of labor. High rates of breech presentation are also seen in fetuses with Down's syndrome and other chromosome abnormalities and neuromuscular disorders.
• Preterm Delivery: About one-third of breech presentations in labor are identified in pregnancies that are less than 37 weeks along, mostly because fetuses are more likely to be in a breech presentation earlier in pregnancy and have not yet turned around.
• Risks to the Mother: One of the risks is from classical cesarean section, in which the very premature breech baby (usually in pregnancies less than 28 weeks) is delivered by cutting the uterus from the bottom to the top, rather than from side to side across the lower-most portion as in a typical cesarean delivery. In an early pregnancy, the lower segment of the uterus is not fully developed and therefore unavailable for the uterine incision.

For more information on breech presentation, go to Management of Difficult Labor, and Breech Delivery.