(Postdate Pregnancy; Postdates; and Prolonged Pregnancy)
A normal pregnancy lasts 38 to 42 weeks. A post-term pregnancy lasts longer than 42 weeks. This raises the risk of certain health problems. Proper prenatal care can improve outcomes.
The most common cause is an incorrect due date. In other people, the exact cause is not known. Changes in hormone levels or certain defects with the baby may play a role.
Things that may raise the risk are:
- Prior post-term pregnancy
- First pregnancy
- Older age of the mother
- Having a boy
There are no symptoms.
The doctor will review your history to make sure the due date is right. You may need:
The goal of treatment is for labor to begin. Options are:
Some women and their healthcare providers choose to wait for labor to begin on its own. During this time, the doctor will watch the baby’s heart rate, fluid levels around the baby, and the baby's breathing and movements.
The doctor may start labor if there are any problems or the pregnancy lasts longer than 42 weeks.
If labor has not started on its own, there are ways the doctor can start it. These include:
- Medicines to help soften and open the cervix.
- Breaking the water by making a small tear in the sac around the baby
- Separating the membranes around the baby by running a finger around the neck of the cervix
- Giving a medicine called oxytocin to start contractions
Starting labor rather than waiting lessens the chance of needing a cesarean section.
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There is no way to prevent a post-term pregnancy.
The American College of Obstetricians and Gynecologists
Office on Women's Health
The Society of Obstetricians and Gynaecologists of Canada
Women's Health Matters—Women's College Hospital
Labor induction. EBSCO DynaMed website. Available at: https://www.dynamed.com/management/labor-induction. Accessed September 15, 2021.
Labor induction. Family Doctor—American Academy of Family Physicians website. Available at: https://familydoctor.org/labor-induction. Accessed September 15, 2021.
Postterm pregnancy. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/postterm-pregnancy. Accessed September 15, 2021.
Pregnancy: What to expect when you're past your due date. Family Doctor—American Academy of Family Physicians website. Available at: https://familydoctor.org/pregnancy-expect-youre-past-due-date. Accessed September 15, 2021.
Last reviewed July 2021 by EBSCO Medical Review Board Mary-Beth Seymour, RN Last Updated: 9/15/2021