Near the end of a term pregnancy, the function of the placenta decreases, providing fewer nutrients and less oxygen to the fetus.
Low blood sugar (glucose) is a particular problem in postterm newborns.
Postterm newborns have dry, peeling, loose skin and may appear abnormally thin because they have not received sufficient nutrition at the end of the pregnancy.
The diagnosis is based on the appearance of the newborn and the estimated date of delivery.
Typically treatment focuses on providing good nutrition and general care.
Some postterm newborns are not breathing at birth and need to be revived (resuscitated).
(See also Overview of General Problems in Newborns Overview of General Problems in Newborns Problems in newborns may develop Before birth while the fetus is growing During labor and delivery After birth About 9% of newborns need special care after birth due to prematurity, problems... read more .)
Gestational age refers to how far along the fetus is. The gestational age is the number of weeks between the first day of the mother's last menstrual period and the day of delivery. This time frame is often adjusted according to other information doctors receive, including the results of early ultrasound scans, which give additional information regarding the gestational age. The baby is estimated to be due (the due date) at 40 weeks of gestation.
Newborns are classified by gestational age as
Full term: Delivered at 37 to before 41 weeks of gestation
Late term: Delivered at 41 to before 42 weeks of gestation
Postterm: Delivered at 42 weeks or more of gestation
Postterm delivery is much less common than preterm (premature) delivery Preterm (Premature) Newborns A preterm newborn is a baby delivered before 37 weeks of gestation. Depending on when they are born, preterm newborns have underdeveloped organs, which may not be ready to function outside of... read more . Why a pregnancy continues beyond term is usually unknown. Women who have had one postterm delivery are at increased risk of having another one.
Near the end of a term pregnancy, the level of amniotic fluid decreases Problems With Amniotic Fluid Amniotic fluid is the fluid that surrounds the fetus in the uterus. The fluid and fetus are contained in membranes called the amniotic sac. Problems with amniotic fluid include Too much amniotic... read more and the placenta (the organ that provides nourishment to the fetus) becomes smaller and less effective in providing oxygen and nutrients. To compensate, the fetus begins to use its own fat and carbohydrates (sugars) to provide energy. As a result, its growth rate slows, and its weight may even decrease.
Complications during and after delivery
If the placenta shrinks enough, it may not provide adequate oxygen to the fetus, particularly during labor (see Perinatal asphyxia Perinatal asphyxia Birth injury is damage that occurs as a result of physical pressure during the birthing process, usually during transit through the birth canal. Many newborns have minor injuries during birth... read more ). A lack of adequate oxygen may result in fetal distress Fetal Distress Fetal distress refers to signs before and during childbirth indicating that the fetus is not well. Fetal distress is an uncommon complication of labor. It typically occurs when the fetus has... read more (signs that the fetus is not well) and, in extreme cases, may result in injury to the brain and other organs.
Fetal distress can cause the fetus to pass meconium (the fetus' stools) into the amniotic fluid. The fetus may reflexively take deep, gasping breaths triggered by the distress and thereby inhale the meconium-containing amniotic fluid into the lungs before birth. As a result, the newborn may have difficulty breathing after delivery (meconium aspiration syndrome Meconium Aspiration Syndrome Meconium aspiration syndrome is trouble breathing (respiratory distress) in a newborn who has breathed (aspirated) a dark green, sterile fecal material called meconium into the lungs before... read more ).
If the pregnancy continues significantly beyond term, the fetus may die.
After delivery, postterm newborns are prone to developing low blood sugar (glucose) levels (hypoglycemia Hypoglycemia Hypoglycemia is abnormally low levels of sugar (glucose) in the blood. Hypoglycemia is most often caused by medications taken to control diabetes. Much less common causes of hypoglycemia include... read more ) because they have exhausted their supply of stored fat and carbohydrates.
Symptoms of Postterm Newborns
Postterm newborns often have dry, peeling, loose skin and may appear abnormally thin (emaciated), especially if the function of the placenta was severely reduced. The fingernails and toenails are long. The umbilical cord and nails may be stained green if meconium was present in the amniotic fluid.
Diagnosis of Postterm Newborns
Appearance of the newborn
Estimated due date
The diagnosis of postterm is based on the newborn's appearance after birth and on the calculated gestational age.
Treatment of Postterm Newborns
Treatment of complications
If a pregnancy goes beyond term, inducing labor in the mother can decrease the risk of newborn death, decrease the need for cesarean delivery Cesarean Delivery Cesarean delivery is surgical delivery of a baby by incision through a woman’s abdomen and uterus. In the United States, up to 30% of deliveries are cesarean. Doctors use a cesarean delivery... read more , and decrease the possibility that the baby will have meconium aspiration syndrome. Postterm newborns who have low oxygen levels and fetal distress may need to be urgently delivered by cesarean delivery and may need to be revived (resuscitated) at birth.
If the baby has breathed meconium into the lungs or is having trouble breathing because of another problem, doctors may give an injection of surfactant Underdeveloped lungs A preterm newborn is a baby delivered before 37 weeks of gestation. Depending on when they are born, preterm newborns have underdeveloped organs, which may not be ready to function outside of... read more (a material that coats the inside of the air sacs and makes it easy to breathe). A machine that helps air get in and out of the lungs (ventilator Mechanical Ventilation Mechanical ventilation is use of a machine to aid the movement of air into and out of the lungs. Some people with respiratory failure need a mechanical ventilator (a machine that helps air get... read more ) and oxygen may be needed to support breathing.
Sugar (glucose) solutions given by vein (intravenously) or frequent breast milk/formula feedings are given to prevent or treat hypoglycemia.
If complications do not occur, the major goal is to provide good nutrition so that postterm newborns can catch up to the weight that is appropriate for them.