Postmaturity is more likely when a mother has had one or more previous post-term pregnancies. Sometimes a mother s pregnancy due-date is miscalculated because she is not sure of her last menstrual period. A miscalculation may mean the baby is born earlier or later than expected. Postmature babies are born at the very end, or past, the normal length of pregnancy. The placenta, which supplies babies with the nutrients and oxygen from the mother s circulation, begins to age toward the end of pregnancy, and may not function as efficiently as before.
Risks can increase during labor and birth for a fetus with poor oxygen supply.
Problems may occur during birth if the baby is large. Postmature babies may be at risk for meconium aspiration, when a baby breathes in fluid containing the first stool. The following are the most common symptoms of postmaturity. However, each baby may show different symptoms of the condition. Symptoms of postmaturity may resemble other conditions or medical problems.