Referring to a baby born after the usual gestation period of 42 weeks.
Term referring to an infant born at 42 weeks or more that is, two or more weeks after the due date, normally calculated as 40 weeks from the beginning of the woman’s last menstruation. Postmaturity is a problem because the placenta, which nourishes the developing fetus, no longer does its job as efficiently late in the pregnancy, after about the 30th week. The child may be larger-boned than average and have less moldable bones because of the longer development. Indeed, largeness itself is sometimes a cause of post-maturity if the baby’s head is too big to descend properly. All of these factors make for difficult delivery and attendant damage, with the risk of stillbirth much increased by the 43rd and 44th weeks of pregnancy. To avoid this, doctors often act by the 42nd week to either induce labor (if appropriate) or to perform a cesarean section. The baby itself will often look gaunt, since fat has been lost from the body, and will have wrinkled, peeling skin and long fingernails. There is often considerable imbalance in the key minerals in the blood, notably calcium and potassium, which needs correction to prevent seizures and possible neurological damage.
To an infant born after an estimated 42 weeks gestation, who exhibits findings consistent with post-maturity syndrome.