Over the last 30 years, labor induction rates have tripled [1]. Why have they risen so rapidly, and has this increase been for the betterment of fetal and maternal health? In 2018, the ARRIVE trial seemed to suggest that labor induction for low-risk, first-time mothers at 39 weeks gestation was safer than waiting for labor to start on its own. But a 2024 study from Victoria, Australia published in the journal Birth Issues In Perinatal Care calls the ARRIVE trial’s findings into question [2].
What did the ARRIVE trial find?
Since its publication in 2018, the ARRIVE trial has been cited as evidence that elective inductions at 39 weeks are safer than an expectant management approach to birth (i.e., letting labor start on its own). Pre-2018, however, induction of labor was widely understood to increase the risk of Cesarean section (C-section), compared to expectant management. While induction has a place in evidence-based perinatal care, historically, it was not encouraged for low-risk women.
But the 2018 ARRIVE trial (A Randomized Trial of Induction Versus Expectant Management), published in the New England Journal of Medicine, wanted to assess whether elective induction at 39 weeks gestation of pregnancy might be a safer birth plan for low-risk first-time moms and their babies [3]. In this trial that took place at 41 hospitals across the United States, the researchers randomly assigned 3,062 low-risk women to be induced at 39 weeks (the experimental group), and 3,044 low-risk women to an expectant management approach to labor (the control group). “Expectant management” during the trial meant that women in the control group could go into labor naturally, be induced for medical reasons, or choose induction after 40 weeks and 5 days gestation—unlike the women in the experimental group, who were simply induced at 39 weeks.
Even though the ARRIVE trial found that induction did not significantly decrease stillbirth occurrences or neonatal death, they did report a 3% lower rate of C-Section (18.6%) for the induction group compared to the expectant management group (22.2%). They also found that the induction group was 5% less likely to develop high blood pressure, and they were discharged from the hospital earlier than the expectant management group. Based on these findings, the researchers concluded that elective induction at 39 weeks might reduce C-Section risk compared to expectant management of labor.
What explains the unusual findings of the ARRIVE trial?
Again, the conventional wisdom prior to ARRIVE was that elective induction would increase a woman’s risk of C-Section. So, ARRIVE’s findings were somewhat unexpected! However, several factors are worth noting when unpacking this trial and its conclusions about labor induction.
For example, the healthcare providers for the experimental (39-week induced mothers) group were instructed to be diligent in best practices for labor induction, such as waiting longer for the women to give birth vaginally than many providers do before recommending a C-Section. This may be why the C-Section rate for the induced mothers was only 19%, even though the U.S. average is significantly higher: 32.4% of all births in 2023.
Additionally, the trial was not necessarily representative of low-risk women who elect to be induced, since participants didn’t get to choose whether they’d be in the induction group or the spontaneous labor group. In fact, 73% of the women who were asked to participate declined—perhaps because they weren’t able to choose which arm (experimental or control) in which they would ultimately end up, and may have had strong preferences for one over another.
Australian research study contradicts ARRIVE findings
New research out of Victoria, Australia challenges whether real-life birth scenarios show comparable results to the highly-controlled ARRIVE trial.
Like the ARRIVE researchers, the Australian researchers also aimed to examine the association between induced labor and Cesarean birth. But rather than having a controlled group study like ARRIVE did, the Australian researchers used the Victorian Perinatal Data Collection from 2010-2018 for every birth in Victoria after 20 weeks gestation (a total of 640,191 births), to assess induction rates and their relationship to caesarean rates.
The Australian researchers found that when labor was induced in low-risk women from 37 to 41 weeks gestation, the rates of C-sections were higher by approximately 23-43%, compared to women who went into labor on their own.
“Induction of labor and cesarean birth in lower-risk nulliparous women at term: A retrospective cohort study”
The Australian researchers found that when labor was induced in low-risk women from 37 to 41 weeks gestation, the rates of C-sections were higher by approximately 23-43% compared to women who went into labor on their own. They did find that the perinatal mortality rate was slightly higher among the expectant management group, but only after 40 weeks gestation. Ultimately, the researchers recommended that women be fully informed about the risks and benefits of elective inductions.
If your provider offers induction, use this tool to help you decide
The Australian research, reflecting real-world experiences, confirms what many already knew: that low-risk pregnant women often fare better when they’re allowed to go into labor on their own.
If you are offered an induction, especially for non-emergent reasons, you can use the acronym BRAIN from the International Doula Institute as a tool to help you evaluate this suggested intervention:
Benefit: What are the benefits for me and/or my baby?
Risks: What risks does this plan introduce for me and/or my baby?
Alternatives: What alternatives are available?
Intuition: How am I feeling about this decision?
Nothing: If I choose to do nothing right now, what risks and benefits are introduced?
As with everything in women’s health, you deserve to be an informed participant in your healthcare. Every woman, birth, and baby is different, meaning induction will make sense for some women. But the Australian research is a strong reminder that letting nature take its course should be the default option for women (and their babies) who don’t necessitate intervention. No matter what, understanding the risks and benefits of every option will allow you to be more at peace with whatever birth decision you make.
Additional Reading:
Is a “big baby” a good reason to have an induction?
I’m being induced. Do I have options besides Pitocin?
Induction drug Pitocin is not the same as natural oxytocin: Some cautions for new moms
