Waiting for the birth of a child is an exciting and anxious time. Most women give birth between 38 and 42 weeks of pregnancy. However, very few babies are born on their due date. It is normal to give birth as much as three weeks before or two weeks after your due date.

Your Due Date
The average length of pregnancy is 280 days, or 40 weeks from the first day of a woman's last menstrual period. It can be hard to predict the exact date. Only 5 percent of babies are born on the exact due date.

Tests for Fetal Well-Being
Babies often are not born by the time of their due date. When this occurs, there are a number of tests that can help the doctor check on the health of the baby.

• A kick count
• The nonstress test and the contraction stress test
• Ultrasound
• A biophysical profile

Labor Induction
If you have passed your due date, your doctor may discuss inducing labor. Labor is induced to cause a pregnant woman's cervix to open (dilate) and thin out (efface) to prepare for the vaginal birth of her baby.

Labor induction carries some risks. You and your baby will be monitored throughout the process. The following methods are used for starting labor:

• Stripping the membranes.
• Ripening or dilating the cervix.
• Rupturing the amniotic sac.
• Oxytocin. This is a hormone that causes contractions.
• Prostaglandin agents. These are a type of medicine that can be used to induce labor.

There can be some complications:

• Change in fetal heart rate
• Increased risk of infection to mother and baby
• The umbilical cord comes out before the baby or is pinched as the baby moves
• Uterine rupture

Risks
About 10 percent of normal pregnancies go past 42 weeks. These are called postterm pregnancies. Problems occur in only a few postterm pregnancies. In fact, about 95 percent of babies born between 42 and 44 weeks are born without problems.

There are a number of reasons your baby may be in danger after 42 weeks. After this time, the placenta may not function as well. Also, as the baby grows, the amount of amniotic fluid may begin to decrease. If pregnancy goes past 42 weeks, a baby has a higher risk of certain problems:

• Dysmaturity syndrome
• Macrosomia
• Meconium aspiration

Postterm pregnancy may increase the chance of cesarean birth.

Finally . . .
Very few babies are born on their exact due date. Most babies born after their due date are born healthy. Tests and careful monitoring during the last weeks of pregnancy and during labor can help ensure the best possible outcome for you and your baby.

This excerpt from ACOG's Patient Education Pamphlet is provided for your information. It is not medical advice and should not be relied upon as a substitute for visiting your doctor. If you need medical care, have any questions, or wish to receive the full text of this Patient Education Pamphlet, please contact your obstetrician-gynecologist.