Definition
A normal pregnancy lasts 38 to 42 weeks. A post-term pregnancy lasts longer than 42 weeks. The risk of certain health problems is higher in post-term pregancies. During this time, your doctor will watch you closely for changes.
Causes
The exact cause is not known. Changes in hormone levels or certain defects with the baby may play a role.
Many times, it is caused by a wrong due date.
Risk Factors
Factors that may increase the risk of a post-term pregnancy include:
- First pregnancy
- Prior post-term pregnancy
- Having a boy
- Obesity
- Older age of the mother
Diagnosis
Your doctor will review your history to make sure the due date is right. You may need:
- Ultrasound —To see how much fluid is around the baby, what position the baby is in, or to check on your baby's movements.
- Fetal monitoring—To check the baby's heartbeat.
Your doctor will check your cervix for signs of labor. Near the end of pregnancy, the cervix gets softer and starts to open up.
Treatment
Talk with your doctor about the best treatment plan for you. Treatment options include:
Close Monitoring
Some women and their doctors 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.
Your doctor may start labor if you have any problems or your pregnancy lasts longer than 42 weeks.
Starting Labor
If labor has not started on its own, there are ways your doctor can start it. These include:
- Medicines to help soften and open the cervix.
- Break your water by making a small tear in the sac around the baby. It does not cause pain and can start contractions.
- Separate the membranes around your baby by running a finger around the neck of the cervix.
- Give a medicine called oxytocin. Oxytocin can start contractions, and keep them strong and regular.
Starting labor rather than waiting lessens the chance of needing a cesarean section.
| Full Term Fetus with Intact Membranes |
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Prevention
There is no way to prevent a post-term pregnancy.
Do not try to start labor yourself with home remedies. They can cause harm to you and your baby.
RESOURCES
Office on Women's Health https://www.womenshealth.gov
The American College of Obstetricians and Gynecologists https://www.acog.org
CANADIAN RESOURCES
The Society of Obstetricians and Gynaecologists of Canada https://www.sogc.org
Women's Health Matters—Women's College Hospital http://www.womenshealthmatters.ca
References
Briscoe D, Nguyen H, Mencer M, Gautam N, Kalb DB. Management of pregnancy beyond 40 weeks’ gestation. Am Fam Physician. 2005;71(10):1935-1941.
Labor induction. EBSCO DynaMed Plus website. Available at: https://www.dynamed.com/topics/dmp~AN~T115335/Labor-induction . Updated October 11, 2016. Accessed March 6, 2019.
Labor induction. Family Doctor—American Academy of Family Physicians website. Available at: https://familydoctor.org/labor-induction. Updated February 1, 2016. Accessed March 6, 2019.
Pregnancy: What to expect when your due date has passed. Family Doctor—American Academy of Family Physicians website. Available at: https://familydoctor.org/pregnancy-expect-youre-past-due-date. Updated November 2, 2016. Accessed March 6, 2019.
Postterm pregnancy. EBSCO DynaMed Plus website. Available at: https://www.dynamed.com/topics/dmp~AN~T116607/Postterm-pregnancy . Updated November 23, 2015. Accessed March 6, 2019.
Sanchez-Ramos L, Olivier F, Delke I, Kaunitz AM. Labor induction versus expectant management for post-term pregnancies: a systematic review with meta-analysis. Obstet Gynecol. 2003;101(6):1312-1318.
Revision Information
- Reviewer: EBSCO Medical Review Board Mary-Beth Seymour, RN
- Review Date: 03/2019
- Update Date: 03/06/2019