Inducing labor, artificially starting labor with medical interventions rather than waiting for labor to naturally occur, is generally recommended only in cases when a delivery has failed to progress or if a complication develops. However, a new study suggests that for normal pregnancies, inducing labor at 39 weeks has some positive benefits.
The ARRIVE trial, a randomized controlled trial in the New England Journal of Medicine, randomized about 6,000 healthy women with normal first pregnancies to either have labor induced at 39 weeks or wait until labor naturally occurred. There was no differences in rates of stillbirth or severe complications for the newborn. The group of women who had labor induced had slightly lower rates of c-sections and hypertensive disorders of pregnancy, which goes against conventional wisdom that inducing labor leads to more c-sections.
Do these results mean we should induce labor in all healthy women at 39 weeks? It’s not that simple. Clinicians, researchers, and patient advocates who study maternal health have pointed out several important reasons why we shouldn’t rush to induce labor.
Study results are not always generalizable to the broader population.
The ARRIVE trial was done under optimal conditions, with participants who all had low-risk pregnancies, no medical complications, and relatively young (average age 23-24). Even more importantly, all of the women participating in the study had agreed to potentially be induced, which presents the possibility of selection bias. Most women want to make their own decision about whether or not to have labor induced (as shown by the large proportion of eligible patients who declined to participate in the trial) so women who participated in the study were more motivated to undergo induction compared to the general population.
Dr. Neel Shah, Assistant Professor of Obstetrics, Gynecology and Reproductive Biology at Harvard Medical School, pointed out on Twitter that the induction process was managed extremely carefully in the study, which does not always happen in practice:
“All inductions are not of equal quality. Some are done well, some are not. In many settings there are significant pressures to expedite labor; in these settings prolonged inductions may truly increase the risk of cesarean.”
The hospitals that provided care in the study had plentiful resources and the clinicians knew they were being studied, which may have made them be more careful in sticking to the protocol for when to provide a c-section. In short, “Trial outcomes resulted from who was induced and way they were induced, not from the decision to induce,” writes Shah.
The study did not measure some important outcomes
The ARRIVE study provides important information about outcomes with induced labor, including neonatal complications, c-section rate, and hypertensive disorders. However, there is still much we don’t know about the effects of inducing labor on health for newborns and mothers. For example, the National Partnership for Women & Families identified research gaps in their recent blueprint:
- What are the effects of using synthetic oxytocin (a medication used to induce labor) on immediate breastfeeding and postpartum hemorrhage; and breastfeeding, maternal behaviors, mother-baby attachment and maternal mood in the following days and weeks?
The ARRIVE study measured all outcomes within the time frame of delivery, according to their clinical trial report. The lead author also mentioned that they followed up with the women in the study 4-8 weeks after the delivery to ask them about their experience and sense of agency throughout the process. However, it does not appear that outcomes such as breastfeeding or mother-baby attachment were measured in this study.
Shared decision making: Working forwards, not backwards
The study authors do not claim that induction at 39 weeks is the right choice for everyone; they emphasize that patients and families need to be at the center of this decision. However, it is important that we interpret this study correctly to avoid further overmedicalizing birth.
The study shows that for low-risk patients who want to be induced, induction (when done properly and patiently) can be a safe option that slightly lowers the risk of c-section. But it would be misinterpreting the study to tell patients that if they want a lower risk of c-section, they should choose induction. We need to start with the patient’s decision and go from there, not start with the outcome and work backwards.
We have to be wary of indication creep; just because induction may be safe for a certain population of healthy, low-risk patients who want to be induced does not mean induction will have the same outcomes for other populations. If we make the assumption that induction is better than expectant management, we will begin looking for more excuses to induce.
Dr. Chitra Akileswaran, ob-gyn and lecturer at Harvard Medical School, makes an important point about the message that these trials send to the ob-gyn community and women in general:
“Our research agenda needs to reflect the Qs most pressing for women today. Which is why the ARRIVE trial disappoints. It prioritizes ‘nice to have’ data that allows us more control over labor, rather than ‘must have’ data that honors women’s abilities to birth how they want.”
Trials like ARRIVE are more than just fodder for an academic debate.
They send a message from the OB community to the public about how we philosophically approach birth. And fundamentally, whether we trust women’s bodies to do the job. 1/
— Chitra Akileswaran (@chitra_mdmba) August 10, 2018