What is the due date and what does it mean?

Your due date is used as a guide for checking your pregnancy’s progress and the baby’s growth and age. Health care providers often use more than one method to set the due date. Ultrasound performed between 18 weeks and 20 weeks of pregnancy often is used to help confirm the age of a fetus.

What is postterm pregnancy?

A postterm pregnancy is one that lasts 42 weeks or longer. Women who are having a baby for the first time or who have had postterm pregnancies before may give birth later than expected. However, the most common cause of postterm pregnancy is an error in calculating the due date. When a postterm pregnancy truly exists, the cause usually is unknown.

What are the risks associated with postterm pregnancy?

After 42 weeks, the placenta may not work as well as it did earlier in pregnancy. Also, as the baby grows, the amount of amniotic fluid may begin to decrease. Less fluid may cause the umbilical cord to become pinched as the baby moves or as the uterus contracts.

If pregnancy goes past 42 weeks, a baby has an increased risk of certain problems, such as dysmaturity syndromemacrosomia, or meconium aspiration. There also is an increased chance of cesarean delivery.

What tests can be performed in cases of postterm pregnancy?

When a baby is not born by the due date, tests can help the health care provider check on the baby’s health. Some tests, such as a kick count, can be done on your own at home. A kick count is a record of how often you feel your baby move. Others are done in the health care provider’s office or in the hospital. These tests involve electronic fetal monitoring and include the nonstress test, biophysical profile, and contraction stress test.

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What is electronic fetal monitoring?

Electronic fetal monitoring uses two belts placed around the mother’s abdomen to hold instruments that measure fetal heart rate and the strength of uterine contractions. This method is used to perform the following tests for fetal well-being:

  • Nonstress test—The mother pushes a button each time she feels the baby move. This causes a mark to be made on a paper recording of the fetal heart rate.
  • Biophysical profile—This test combines the results of electronic fetal monitoring and an ultrasound exam. It checks the baby’s heart rate (using the nonstress test) and estimates the amount of amniotic fluid. The baby’s breathing, movement, and muscle tone also may be checked.
  • Contraction stress test—The baby’s heart rate is measured when the mother’s uterus contracts. The contractions are induced, and changes in the fetus’s heart rate are noted.

What is labor induction?

Labor induction is the use of medication or other methods to bring on labor. Labor is induced to cause a pregnant woman’s cervix to open and to prepare for vaginal birth. Most health care providers wait 1–2 weeks after a woman’s due date before considering inducing labor.

How is labor induced?

Methods used to induce labor include:

  • Ripening or dilating the cervix—Prostaglandins may be used to soften the cervix and to cause the uterus to contract. Special devices can be used to dilate the cervix.
  • Stripping or sweeping the amniotic membranes—Your health care provider sweeps a finger over the thin membranes that connect the amniotic sac to the wall of your uterus. Women who have this procedure are more likely to have contractions and may go into labor within 48 hours.
  • Rupturing the amniotic sac—Your health care provider makes a small hole in the amniotic sac to release the fluid (“breaking the water”). Most women go into labor within hours of their water breaking
  • Using oxytocin—This hormone, given through an intravenous (IV) tube in your arm, causes the uterus to contract.


Amniotic Fluid: Water in the sac surrounding the fetus in the mother’s uterus.

Cesarean Delivery: Delivery of a baby through an incision made in the mother’s abdomen and uterus.

Dysmaturity Syndrome: A condition in which the fetus is malnourished. He or she is born with a long and lean body, an alert look on the face, lots of hair, long fingernails, and thin wrinkled skin.

Macrosomia: A condition in which a fetus grows very large.

Meconium Aspiration: A condition in which the baby inhales a greenish substance that builds up in the bowels of a growing fetus. This blocks the airways and causes the baby to gasp for air.

Placenta: Tissue that provides nourishment to and takes waste away from the fetus.

Prostaglandins: Chemicals that are made by the body that have many effects, including causing the muscle of the uterus to contract, usually causing cramps.

Ultrasound: A test in which sound waves are used to examine the fetus.

Umbilical cord: A cord-like structure containing blood vessels that connects the fetus to the placenta.

Uterus: A muscular organ located in the female pelvis that contains and nourishes the developing fetus during pregnancy.

If you have further questions, contact your obstetrician–gynecologist.

Designed as an aid to patients, this document sets forth current information and opinions related to women’s health. The information does not dictate an exclusive course of treatment or procedure to be followed and should not be construed as excluding other acceptable methods of practice. Variations, taking into account the needs of the individual patient, resources, and limitations unique to the institution or type of practice, may be appropriate.