What Changes in Pregnancy at 41 Weeks

At 41 weeks, you are officially one week past your due date, but you are still within the normal range for delivering your baby. Approximately 10 percent of pregnancies reach 41 weeks. But at 41 weeks, your doctor will start a conversation about timing of your baby’s birth. This is the week when most doctors will begin discussing induction. The discussion is clearly worth having. Your doctor should talk with you about what the evidence shows about inductions at 41 weeks and what the risks and benefits actually are. The decision about whether or not to have an induction is yours.

At 41 weeks, your placenta has been functioning for 287 days or more. Placental aging is a real process. The placenta accumulates calcium deposits, the blood vessels within the placenta become less efficient, and the transfer of oxygen and nutrients to your baby can decline. This process does not happen on a fixed schedule. It will vary significantly from one pregnancy to another. However, the statistical risk of adverse outcomes for you and your baby begins to increase at 41 weeks and rises more steeply at 42 weeks.

The two primary concerns at 41 weeks are oxygen insufficiency and meconium aspiration. Placental insufficiency can develop when the aging placenta can no longer deliver adequate oxygen to your baby, which can lead to fetal distress. Monitoring your baby’s movements with the daily kick test helps you track if your baby’s oxygen supply is compromised.

Meconium is your baby’s stool. Your baby’s first bowel movement usually occurs after your baby’s birth. By week 42, your baby may pass meconium before birth. When your baby’s stool passes before being born, your baby may inhale the meconium in the amniotic fluid. This can cause your baby serious respiratory complications.

A recent study compared either elective induction at 39 weeks with management of pregnancy until 41 weeks or later. The trial found that elective induction at 39 weeks did not increase the rate of C-section delivery and was associated with moderately lower rates of some complications. The implications for 41-week management are indirect but relevant. This trial reinforced that induction, when appropriately performed, does not carry the C-section risk that was historically assumed. The fear that induction leads to C-section has been a widely held clinical belief for decades, but this belief is not supported by this study.

The current evidence-based recommendation, endorsed by the American College of Obstetricians and Gynecologists (ACOG), is that induction of labor should be offered at 41 weeks and recommended by 42 weeks for low-risk pregnancies. This is not a mandate. It is a recommendation based on the balance of risks. The conversation at 41 weeks should be a genuine informed consent discussion, with the patient making the decision whether or not to have an induction.

At 41 weeks, there should be a biophysical profile to evaluate the health your baby. This profile combines ultrasound imaging and a nonstress test to assess factors such as fetal movement, muscle tone, breathing, heart rate, and the amount of amniotic fluid. A normal profile is reassurance that the placenta is still functioning adequately. If you choose not to have an induction, this profile should be performed twice weekly from 41 weeks forward.

Induction is not in any way a failure. Induction can be used to deliver your baby when tests suggest the risk of continuing to wait for natural labor and delivery will harm your baby. When your doctor has answered your questions, the decision to have an induction is yours, made in cooperation with your doctor.