Inducing labor at 39 weeks in low-risk first-time mothers does not increase the risk of maternal or fetal complications but does significantly lower the risk of cesarean section, concludes a new study commonly referred to as the ARRIVE Trial published in the New England Journal of Medicine and sponsored by the National Institutes of Health. The findings contradict the long-held belief that induction increases the frequency of cesarean delivery.
During all three of my pregnancies, I planned homebirths attended by a certified nurse-midwife. I wanted to avoid as many interventions as possible and felt most comfortable giving birth at home. I fully trusted my two midwives, both of whom had excellent histories. My first baby arrived at 36 weeks 2 days, my second at 37 weeks 3 days, and my third at 38 weeks 2 days. All three of my labors began spontaneously and proceeded without any major problems.
Previous studies found that induction increased the risk of adverse outcomes for mothers and babies and increased the risk of cesarean section, a surgery to deliver a baby in which the baby is removed through an incision in the mother’s abdomen. Past research, however, compared women who went into labor spontaneously with women who were induced at the same points in their pregnancy. Previous studies thus included inductions before 39 weeks, when complications developed, and overdue pregnancies past 40 weeks. Including pregnancies at any point in pregnancy resulted in a link between induction and cesarean delivery.
Explained principal investigator, Dr. William Grobman, a professor of OB-GYN at Northwestern Medicine, “‘People misinterpreted that data'” to mean that inductions at any point in a pregnancy carry more risk.”
The present study randomly assigned low-risk first-time mothers at 38 weeks 0 days to 38 weeks 6 days of gestation to labor induction at 39 weeks 0 days to 39 weeks 4 days or to expectant management. A total of 3,062 women participated in the induction group and 3,044 in the expectant-management group for a total of more than 6,100 first-time, healthy pregnant women across the country. The trial took place at 41 facilities across the United States consisting of university and community hospitals.
Among all the participants, perinatal death or severe neonatal complications occurred in 4.3% of babies in the induction group and in 5.4% in the expectant-management group. Cesarean section occurred in 18.6% of the induction group versus 22.2% in the expectant-management group. Other complications were also lower in the induction group versus the expectant-management group including preeclampsia and hypertension (9% versus 14%) and newborns requiring respiratory support (3% versus 4%). The study did not find other differences in perinatal or maternal outcomes.
Based on the results, the authors of the ARRIVE Trial suggest that policies aimed at avoiding elective labor induction among low-risk first-time mothers at 39 weeks are unlikely to reduce the rate of cesarean section.
Commented study co-author Dr. Robert Silver, chairman of obstetrics and gynecology at University of Utah Health, “If you deliver the baby before 39 weeks, then there’s an increased risk of medical problems. Once you get to 39 weeks, the baby’s developed enough that there’s really no benefit.”
The American College of Obstetricians and Gynecologists (ACOG) and the Society for Maternal-Fetal Medicine (SMFM) released a statement in response to the results of the study:
“ACOG and SMFM have reviewed the published results of the ARRIVE Trial and determined that it is reasonable for obstetric care providers to offer an induction of labor to low-risk women after discussing the options thoroughly, as shared decision making is a critical element. Women eligible for induction must meet the following criteria:
- “Women who are planning their first delivery, are healthy and have no medical or obstetrical complications.
- “Women who are 39 weeks pregnant and had an ultrasound performed early in the pregnancy to confirm dating.”
ACOG will continue to review the information and subsequent forthcoming analyses to issue clinical guidance as appropriate.
Not all health care professionals agree. Stated Susan Stone, president of the American College of Nurse-Midwives, “It’s going to be appropriate for some women, but the question is, how widely will this be applied, what is going to be the cost to our society of doing that, and could those costs be put to a better use that might be a more non-interventative strategy for reducing cesarean sections?”
Adds Cynthia Gabriel, a medical anthropologist and author of the book Natural Hospital Birth: The Best of Both Worlds, “Personally, I would look at all the practices that we currently do that lead women to have different labors and more cesareans than necessary in their hospital births.”
Silver did clarify that induction is not right for every women. The study found a reduced risk of cesarean and preeclampsia regardless of race or ethnicity and a reduction of pulmonary disease in the baby regardless of race and ethnicity. However, women who desire a more holistic approach can as long as their health care profession deems doing so safe. Said Silver, “People shouldn’t be afraid to go past 39 weeks. This doesn’t mean it’s a better option and that everyone should be induced at 39 weeks. It simply means you aren’t going to cause harm.”
I gave birth to all three of my babies without any interventions after spontaneous labors. None of my pregnancies extended past 39 weeks, with my longest reaching only 38 weeks 2 days. My oldest daughter, who arrived at 36 weeks 2 days, weighed a healthy 7 pounds 5 ounces. Neither she nor I experienced any complications after birth. My second baby developed jaundice, which was treated successfully at home with a biliblanket. I opted for a shot of Pitocin after the birth of my third baby to stop excessive bleeding. Otherwise, my second and third labors and births occurred spontaneously without any problems.
While the results of the ARRIVE Trial are good news for women who want to induce labor at 39 weeks, I personally would still not choose induction unless medically indicated. I believe that pregnancy, labor, and birth are normal physiological processes of the female body. However, I do consider the findings positive for mothers-to-be in general: Women with low-risk first-time pregnancies who want to induce labor can do so during week 39 of pregnancy without worrying about an increased risk of cesarean section or other adverse complications.
Do the results of the ARRIVE Trial change your view of induced labor?
Choosing to Induce Labor at 39 Weeks Reduces Risk of C-sections, Study Finds: https://www.nbcnews.com/health/health-news/choosing-induce-labor-39-weeks-reduces-risk-c-sections-study-n898471
Labor Induction versus Expectant Management in Low-Risk Nulliparous Women: https://www.nejm.org/doi/full/10.1056/NEJMoa1800566
Leaders in Obstetric Care Respond to the Published Results of the ARRIVE Trial: https://www.acog.org/About-ACOG/News-Room/Statements/2018/Leaders-in-Obstetric-Care-Respond-to-the-Published-Results-of-the-ARRIVE-Trial
Practice Advisory: Clinical Guidance for Integration of the Findings of The ARRIVE Trial: Labor Induction versus Expectant Management in Low-Risk Nulliparous Women: https://www.acog.org/Clinical-Guidance-and-Publications/Practice-Advisories/Practice-Advisory-Clinical-guidance-for-integration-of-the-findings-of-The-ARRIVE-Trial
What the ‘Induction at 39 Weeks’ Study Means for Me: https://www.flickr.com/photos/spaceninja/406565017/ (CC BY-NC-SA 2.0) and https://www.flickr.com/photos/megnut/631399663/ (CC BY-NC 2.0)