Late-term pregnancy

Miriam Murray, MD, explains why inducing at 41 weeks is important and discusses some common misconceptions about being induced.

Why is inducing at 41 weeks important?

The short answer is that at 41 weeks the risks of remaining pregnant outweigh the benefits of spontaneous labor. 

The longer answer involves discussion of the risks to both the patient themself and the fetus when a pregnancy continues more than a week beyond the due date. These include the baby growing too large (macrosomia), a syndrome called “fetal postmaturity syndrome,” and, most importantly, an increased risk of perinatal mortality.

Infants that are born after 41 weeks are more likely to be problematically large or 'macrosomic' which means weighing more than 4,500 grams (9 lbs 15 oz). When an infant is macrosomic, the delivery is at risk of a number of complications including cesarean section, hemorrhage, and shoulder dystocia and the baby is at risk of having metabolic problems after birth.

Fetal postmaturity syndrome occurs in around 1/5 of babies who are born more than a week after their due date and ultimately means an infant shows signs that it wasn’t getting the nutrients it needed anymore while it was in the uterus. Before birth, these signs include low amniotic fluid and abnormalities of the fetal heart rate on monitoring. These babies often have had their first bowel movement before they are born, which puts them at risk of breathing problems. After the baby is born, they have dry skin and signs that they stopped growing at the usual rate including lower than expected birth weight and loose skin, in addition to more important problems with breathing and metabolism.

Finally, the risk of perinatal mortality (stillbirth or death soon after birth) increases slightly at 41 weeks (about 1/3 increased risk) but more significantly as patients approach 42 weeks and beyond. When someone is two weeks past their due date, there is twice as much risk of death for the infant and at three weeks the risk quadruples.

What are some common misconceptions about being induced?

Many people think that a patient is more likely to end up with a cesarean section if they are induced, but this actually is not the case. There was a very large study called the ARRIVE Trial that was released in 2018 that showed that there was no increase in the risk of cesarean section in first time moms who were induced at 39 weeks.

There is a perception that being induced is more painful than spontaneous labor. While everyone’s experience is different, labor hurts pretty bad no matter what! There is no evidence that an induced labor is more painful than a spontaneous labor. Here at UI Hospitals & Clinics, we have great options to help support patients in labor whether they want an epidural, IV pain medications, or a birth without any pain medications.

The concept that there is something inherently wrong with it not being 'natural' is a barrier to some patients feeling comfortable with induction. We’re all lucky to live in a time that medical knowledge is growing exponentially and gives us the chance to help improve outcomes. While an induced labor does generally indicate more interventions than a spontaneous labor, that doesn’t mean it is worse. It’s all about a safe and healthy delivery.