For several reasons, an overdue pregnancy can be risky both for the mother and the baby. In addition to higher odds of numerous complications, there's said to be an increased risk of stillbirth in pregnancies that have progressed beyond 42 weeks. But exactly how much increased risk is there? Here is what UpToDate, an online health resource for doctors and patients, has to say about stillbirth risk in an overdue pregnancy:
"The incidence of stillbirth or infant death is increased in pregnancies that continue beyond 42 weeks. However, the risk is relatively small, with only 4 to 7 deaths per 1000 deliveries. By comparison, the risk of stillbirth or infant death in pregnancies between 37 and 42 weeks is 2 to 3 per 1000 deliveries."
So, there is a slightly elevated risk of stillbirth in pregnancies that are overdue, but it's not something you should spend a lot of time worrying about as long as you're seeing your doctor regularly. The increase is not large compared to the stillbirth risk for women who deliver at term, but the elevated risk is one reason why doctors like to closely monitor women with overdue pregnancies and why doctors might recommend induction if you go beyond 42 weeks.
Here are some other questions you might have:
What are the other risks involved in having an overdue pregnancy?
There can be increased complications during delivery when the baby is larger, such as a longer labor and higher risk of birth trauma. The baby may also be more likely to pass the meconium during delivery, which can lead to respiratory complications.
What will doctors do in pregnancies that progress past the due date?
Obstetricians often will increase frequency of prenatal monitoring, meaning they will suggest regular nonstress tests and possibly biophysical (fetal health) profiles. Many doctors will recommend labor induction in pregnancies that are one to two weeks beyond the due date.
Who is at risk of having an overdue pregnancy?
Up to 10% of all pregnancies go past the estimated due date. Women in their first pregnancies and those who have had a postterm pregnancy in the past seem to have the highest risk.
I'm 40 weeks pregnant. My neighbor's doctor induced her at 39 weeks. Why won't my doctor induce me?
People's circumstances differ, and there are many reasons why inductions might be recommended earlier in some situations than in others. In many cases, it is hard to determine with absolute certainty whether a baby is truly ready to be born. Given the higher risk of complications if the baby is born too early (such as if the due date has been miscalculated), many doctors will only recommend induction when it's very clearly necessary. Your doctor probably does not think there is a compelling reason to induce your labor at this time, but as long as your doctor is monitoring you and your baby, there's no need to worry. If you don't go into labor naturally within a week or two, or if any sign of complications develops, it's possible that your doctor might recommend a change of approach.
Want to learn more? See UpToDate's topic, "Patient information: Postterm pregnancy," for additional in-depth medical information.
Norwitz, Errol R. "Patient information: Postterm pregnancy." UpToDate. Accessed: December 2009.