A postterm pregnancy occurs when the baby has not been delivered by the end of the 42nd week. There is no health risk to the mother, but after the 42nd week the fetus may be at risk of malnutrition. Also, if it passes fecal matter -- which usually does not happen until after birth -- and breathes it in, it may develop pnemonia. A doctor may choose to induce labor two weeks past the due date.
The cause of postterm pregnancy is not known. In most cases, however, it is believed that the mother misstated the exact date of her last menstrual period and the pregnancy was not postterm after all. If a woman has had one postterm pregnancy, she has a greater than average chance of this happening again in subsequent pregnancies.
Postterm pregnancy poses no health risk to the mother. However, as the placenta continues to age beyond the 42nd week of pregnancy, its ability to transmit oxygen and nutrients to the fetus may begin to decline. In some cases, this reduction in the transmission of oxygen and nutrients may be severe enough to cause the death of the fetus. If the fetus lives, at birth the baby commonly has a characteristic postterm appearance: wrinkled, cracking, peeling skin; long nails; abundant hair; and little fat tissue beneath the skin.
The postterm baby often passes fecal material called meconium into the amniotic fluid before delivery. If the baby sucks meconium into his lungs at the time of delivery, severe pneumonia may result.
The usual treatment for postterm pregnancy is to periodically check the fetal heartbeat until labor starts on its own or is induced (started artificially). Labor is induced by administering the drug oxytocin (Pitocin) intravenously. Oxytocin stimulates uterine contractions similar to those of normal labor. A fetal monitor is generally used to detect any abnormalities of the fetal heartbeat. Most women with an induced labor experience a normal labor and delivery.
While postterm birth does not endanger the mother, ectopic pregnancy can be fatal. On the next page you'll learn what it is and how it affects the mother.