What is Post-Term Pregnancy?

Post-maturity is when a baby has not yet been born after 42 weeks of gestation, two weeks beyond the normal 40. Post-term, post-maturity, prolonged pregnancy, and post-dates pregnancy all refer to post-mature birth. Post-mature births do not have any harmful effects on the mother, but the fetus, however, can begin to suffer from malnutrition. After the 42nd week of gestation, the placenta, which supplies the baby with nutrients and oxygen from the mother, starts aging and will eventually fail. If the fetus passes fecal matter, which is not typical until after birth, and the child breathes it in, then the baby could become sick with pneumonia. Post-term pregnancy may be a reason to induce labor.

The cause of post-term births is unknown. But post-mature births are more likely when the mother has experienced a previous post-mature birth. Due dates are easily miscalculated when the mother is unsure of her last menstrual period. When there is a miscalculation, the baby could be delivered before or after the expected due date. Post-mature births can also be attributed to irregular menstrual cycles. When the menstrual period is irregular it is very difficult to judge how and when the ovaries would be available for fertilization and subsequently result in pregnancy. Some post-mature pregnancies are because the mother is not certain of her last period, so in reality the baby is not technically post-mature. However, in most first
world countries where gestation is measured by ultrasound scan technology, this is less likely.

Different babies will show different symptoms of post-maturity. The most commons symptoms are dry skin, overgrown nails, creases on the baby's palms and soles of their feet, minimal fat, a lot of hair on their head, and either a brown, green, or yellow discoloration of their skin. Doctors diagnose post-mature birth based on the baby's physical appearance and the length of the mother's pregnancy. Some post-mature babies will show no or little sign of post-maturity.

Once a pregnancy has surpassed the 40 week gestation period, doctors closely monitor the mother for signs of placental deterioration. Towards the end of pregnancy calcium is deposited on the walls of blood vessels and proteins are deposited on the surface of the placenta, which changes the placenta. This limits the blood flow through the placenta and ultimately leads to placental insufficiency and the baby is no longer properly nourished. Induced labor is strongly encouraged if this happens.

Post-term babies may be larger than an average baby, thus increasing the length of labor. The labor is increased because the baby's head is too big to pass through the mother's pelvis. This is called
cephalopelvic disproportion. Caesarean sections are encouraged if this happens.

When post-mature babies are larger than average, forceps or vacuum delivery may be used to resolve the difficulties at the delivery time. Difficulty in delivering the shoulders, shoulder dystocia, becomes an increased risk.

Adopted from wikipedia.com