Postdate Pregnancy

What is postdate pregnancy?

The length of a normal pregnancy is 38 to 42 weeks from the first day of the last menstrual period. A postdate pregnancy is a pregnancy that lasts longer than 42 weeks. Because there are some very serious risks for both mother and baby, your healthcare provider will follow a postdate pregnancy closely.

How does it occur?

Seven percent of all pregnancies are postdates. Sometimes this is because the due date is incorrect. In other cases pregnancies just last longer than normal. Why some pregnancies continue past their due dates is not well understood.

How is it diagnosed?

You and your healthcare provider must first accurately date your pregnancy. It is much easier to calculate an accurate due date early in the pregnancy. This is one reason you need prenatal care early in your pregnancy.

Your provider uses several kinds of information to calculate your due date, including the date of your last menstrual period and how regular your periods are. An ultrasound scan may be used to measure the baby and estimate the due date. This estimate is usually accurate within 7 to 10 days if the ultrasound scan is done during the first half of the pregnancy. Other measurements may be used as well.

How is it treated?

If you go past your due date, the concern is that the placenta is aging. It may no longer be providing enough oxygen and nutrients to your baby.

There are several ways to check the health of an overdue baby:

• a kick count, where you count movements your baby makes during a prescribed length of time
• electronic fetal monitoring (nonstress or contraction stress test)
• ultrasound evaluation (biophysical profile)
• ultrasound measurement of the amount of amniotic fluid

If the health of your baby is unclear or dates are uncertain, your healthcare provider may do an amniocentesis on or around your due date. For this test some amniotic fluid is taken from your uterus. Tests of the fluid can show how mature your baby's lungs are.

Your provider may check for meconium in the amniotic fluid. Meconium is a greenish substance that builds up in your baby's bowels and is normally discharged shortly after birth. If it is discharged into the amniotic fluid before birth, the baby might inhale it. Inhalation of meconium into the lungs can cause breathing problems for the baby at birth. If meconium is found, your baby may be monitored very closely. The baby may need to be delivered right away.

This information helps your provider determine whether it is safe to wait for labor, if it is time to induce labor to deliver the baby, or if a cesarean section is needed.

• At 42 weeks your provider may induce labor, especially if your cervix has ripened and is ready for delivery. (Inducing labor means starting it artificially, such as with medication.) If the cervix has not ripened, medicine may be used to ripen the cervix and help induce labor.
• If the baby appears to be healthy and not in danger, your provider may check you regularly and wait for labor to begin naturally.
• If the baby appears to be at risk of danger, labor may have to be induced, or the baby may be delivered by cesarean section (C section).

What are the risks?

Examples of risks to the baby include:

• If the pregnancy continues, your baby may not receive enough oxygen or nutrients from the blood of an aging placenta. This could stop the baby's growth, injure the baby's brain, or even cause death of the baby.
• The baby may discharge and breathe in meconium which could lead to breathing problems after birth.
• You may get an infection in the uterus that could harm the baby.
• You may develop a problem called oligohydramnios, which means too little amniotic fluid around the baby. It can lead to problems during labor and delivery.
• Low blood sugar.
• Convulsions.

What can be done to prevent stillbirth or harm to the baby?

The most important thing you can do to have a healthy baby is to see your healthcare provider and begin prenatal care as soon as you think you are pregnant.

If you have passed your due date, your provider may avoid possible risks to your baby by inducing labor as your pregnancy nears 41 to 42 weeks. However, there are risks if the baby is not mature and ready to be born. Also, if your cervix is not ready for labor, you could have problems such as prolonged labor and infection. Delivery by cesarean section might become necessary. Make sure that you discuss the risks and options of delivery with your provider.

Developed by RelayHealth.
Published by RelayHealth.
© 2009 RelayHealth and/or its affiliates. All Rights Reserved.