The normal length of pregnancy is
37 to 41 weeks. Early term is from 37 weeks to 38 weeks and 6 days. Full term is 39
weeks to 40 weeks and 6 days. Late term is 41 weeks to 41 weeks and 6 days. Postmaturity
(dysmaturity) is a word used to describe babies born after 42 weeks. Very few babies
born at 42 weeks or later. Because of the risks listed below, obstetric providers
induce delivery before 42 weeks. Other terms often used to describe these late births
include post-term, postmaturity, prolonged pregnancy, and post-dates pregnancy.
Researchers don’t know why some
pregnancies last longer than others. Sometimes a mother’s pregnancy due date is off
because she is not sure of her last menstrual period. Getting the date wrong may mean
the baby is born earlier or later than expected. Getting an ultrasound in the first
weeks (the first trimester) is the most accurate way to tell the date of pregnancy,
unless the date of conception is specifically known, such as with in vitro
Postmaturity is more likely to
happen when a mother has had a post-term pregnancy before. After one post-term
pregnancy, the risk of a second post-term birth increases by 2 to 3 times. Other minor
risk factors include:
- First pregnancy
- Male baby
- Older mother
- Obese mother
- Mother or father with personal history of postmaturity
- White mother
Each baby may show different symptoms of postmaturity. Some of those symptoms are:
- Dry, loose, peeling skin
- Overgrown nails
- Large amount of hair on the head
- Visible creases on palms and soles of
- Small amount of fat on the body
- Green, brown, or yellow coloring of
skin from baby passing stool (meconium) in the womb
Symptoms of postmaturity sometimes
look like other health conditions. Make sure your child sees their healthcare
provider for a diagnosis.
Your baby’s healthcare provider will check:
- Your baby’s physical appearance
- The length of your pregnancy
- How old your baby seems to be
Your healthcare provider will check your unborn baby’s health and look for any problems.
Tests may need to be done such as:
- Nonstress testing. This looks at how the fetal heart rate responds to fetal movement.
- Checking the amount of amniotic fluid
Your healthcare provider may decide
to start your labor early, depending on several things. During labor, your baby’s
rate may be watched with an electronic monitor. This will help spot changes in the
rate caused by low oxygen levels. Changes in your baby’s condition may require a
cesarean section delivery.
Special care of the post-term baby may include:
- Checking for breathing problems caused by baby’s breathing in fluid containing the
first stools (meconium)
- Blood tests for low blood sugar
Post-term babies are born after the
normal length of pregnancy. Because of this they may grow larger than full-term babies.
This may be a problem during labor and delivery, or your baby may need a cesarean
Also, because the placenta ages toward the end of pregnancy, it may not work as well
as before. Concerns from placental aging include:
Less amniotic fluid. This may stop
the baby from gaining weight. Or it may even cause weight loss.
Poor oxygen supply. Babies who don’t
get enough oxygen may have problems during labor and delivery.
Meconium aspiration. Babies who stay
in the uterus longer are more likely to breathe in fluid containing meconium.
Persistent pulmonary hypertension of the
Babies with poor oxygen supply or meconium aspiration are at risk
for blood flowing away from their lungs without picking up oxygen to deliver to the
rest of their body.
Hypoglycemia or low blood sugar. This
happens when the baby has already used up their stores of glucose.
Knowing your due date is the best way to know if your baby may be post-term. Keep
track of the first day of your menstrual period. This can help estimate a baby’s due
date. An ultrasound test early in pregnancy can also help your healthcare provider
figure out your baby’s age by checking the baby’s size. Ultrasound is also a good
way to check the placenta for signs of aging.
- Postmaturity is a word used to describe babies born after 42 weeks.
- Researchers don’t know why some pregnancies last longer than others.
- Postmaturity is more likely to happen when a mother has had a post-term pregnancy
- Your healthcare provider may decide to start your labor early.
- An ultrasound test early in pregnancy can help your healthcare provider figure out
your baby’s age by checking the baby’s size.
Tips to help you get the most from a visit to your child’s healthcare provider:
- Know the reason for the visit and what you want to happen.
- Before your visit, write down questions you want answered.
- At the visit, write down the name of a new diagnosis, and any new medicines, treatments,
or tests. Also write down any new instructions your provider gives you for your child.
- Know why a new medicine or treatment is prescribed and how it will help your child.
Also know what the side effects are.
- Ask if your child’s condition can be treated in other ways.
- Know why a test or procedure is recommended and what the results could mean.
- Know what to expect if your child does not take the medicine or have the test or procedure.
- If your child has a follow-up appointment, write down the date, time, and purpose
for that visit.
- Know how you can contact your child’s provider after office hours. This is important
if your child becomes ill and you have questions or need advice.