Monday Medical: Inducing pregnancy and the Arrive Trial

Susan Cunningham
For SteamboatPilot & Today

For pregnant women, the decision of whether to be induced into labor can be difficult to make. But a recent study, known as the Arrive Trial, is shedding light on the topic.

“Prior to the Arrive Trial, there was a gap in knowledge for induction in labor,” said Dr. Kathryn Feller, an OB/GYN with UCHealth Women’s Care Clinics in Steamboat Springs and Craig. “We knew that elective induction before 34 weeks was not recommended for the baby, and we knew it was helpful after 41 weeks. But for that gap in between, there were questions about whether it was going to cause harm or be beneficial.”

The 2018 research trial was “huge,” Feller said, involving 41 hospitals and a group of 6,000 pregnant women who met several requirements: they had never given birth before, they did not have any pregnancy complications, and their babies were positioned head down. Half of the women were induced at week 39, and the other half received expectant management, which meant they could deliver naturally, be induced for medical reasons, or be induced electively after 40 weeks and 5 days.

“The trial collected all of these low-risk women and asked two questions – does elective induction at 39 weeks decrease bad outcomes for the baby, and does it affect the caesarean delivery rate?” Feller said. “Previously, the thought process was that if a woman was induced unnecessarily, it would increase the C-section rate.”

In fact, the results showed the opposite. Inducing labor at 39 weeks did not harm the baby, and it decreased the rate of cesarean deliveries: 18% of women who were induced at 39 weeks ended up having a C-section, while 22% in expectant management had a C-section. While that difference may seem small, it’s significant, especially when extrapolated over a large group.

“It showed significantly and very clearly that it decreases the C-section rate for women,” Feller said.

While it isn’t clear why this happens, one possibility is that the longer a pregnancy goes on, the less effective the placenta becomes.

“The placenta is the only organ the body develops that’s supposed to have an expiration date,” Feller said. “It has a time stamp. As you approach that time stamp, the placenta doesn’t work as well.”

With her own patients, Feller starts the conversation about elective induction when they are 36 weeks into their pregnancies to help women understand their options.

“Most people haven’t heard about this study, and people often have this thought – whether from friends, moms or grandmas – that induction of labor increases risk of C-section,” Feller said. “We let them know they do have the option of getting induced into labor at week 39, and that it decreases rate of C-section in young healthy women, and doesn’t cause harm to the baby.”

There can be other benefits of inducing labor. Women who chose to be induced at 39 weeks felt like they had more control over the labor and delivery process, and avoided the last weeks of pregnancy, which can often be uncomfortable, Feller said.

If a woman decides to be induced, there are a variety of medications and methods that can be used to help get labor started.

“The misconception of induction is that we’re forcing your body into labor,” Feller said. “Induction uses medication and other methods to convince the body to go into labor, but once it has started, your body should decide to labor on its own, with our help.”

Feller always reminds patients that at the end of the day, the decision on how to proceed is up to them.

“This is all shared decision making,” Feller said. “What’s right for one person is not right for another. The information I give is the best I have, but the most important opinion is the patient’s opinion, and there are no judgements. We’ll support you no matter what, all we want is a healthy mom and a healthy baby.”

Susan Cunningham writes for UCHealth Yampa Valley Medical Center. She can be reached at

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