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A growing body of evidence supports improved or not worsened birth outcomes with nonmedically indicated induction of labor at 39 weeks gestation compared with expectant management. This evidence includes 2 recent randomized control trials. However, concern has been raised as to whether these studies are applicable to a broader US pregnant population.
Objective
Our goal was to compare outcomes for electively induced births at ≥39 weeks gestation with those that were not electively induced.
Study Design
We conducted a retrospective cohort study using chart-abstracted data on births from January 1, 2012, to December 31, 2017, at 21 hospitals in the Northwest United States. The study was restricted to singleton cephalic hospital births at 39+0–42+6 weeks gestation. Exclusions included previous cesarean birth, missing data for delivery type or gestational week at birth, antepartum stillbirth, cesarean birth without any attempt at vaginal birth, fetal anomaly, gestational diabetes mellitus, prepregnancy diabetes mellitus, and prepregnancy hypertension. The rate of cesarean birth for elective inductions at both 39 and 40 weeks gestation was compared with the rate in all other on-going pregnancies in the same gestational week. Maternal outcomes (operative vaginal birth, shoulder dystocia, 3rd- or 4th-degree perineal laceration, pregnancy-related hypertension, and postpartum hemorrhage) and newborn infant outcomes (macrosomia, 5-minute Apgar <7, resuscitation at delivery, intubation, respiratory complications, and neonatal intensive care unit admission) were also compared between elective inductions and on-going pregnancies at 39 and 40 weeks gestation. Logistic regression modeling was used to produce odds ratios for outcomes with adjustment for maternal age and body mass index. Results were stratified by parity and gestational week at birth. Duration of hospital stay (admission to delivery, delivery to discharge, and total stay) were compared between elective inductions and on-going pregnancies.
Results
A total of 55,694 births were included in the study cohort: 4002 elective inductions at ≥39+0 weeks gestation and 51,692 births at 39+0–42+6 weeks gestation that were not electively induced. In nulliparous women, elective induction at 39 weeks gestation was associated with a decreased likelihood of cesarean birth (14.7% vs 23.2%; adjusted odds ratio, 0.61; 95% confidence interval, 0.41–0.89) and an increased rate of operative vaginal birth (18.5% vs 10.8%; adjusted odds ratio, 1.8; 95% confidence interval, 1.28–2.54) compared with on-going pregnancies. In multiparous women, cesarean birth rates were similar in the elective inductions and on-going pregnancies. Elective induction at 39 weeks gestation was associated with a decreased likelihood of pregnancy-related hypertension in nulliparous (2.2% vs 7.3%; adjusted odds ratio, 0.28; 95% confidence interval, 0.11–0.68) and multiparous women (0.9% vs 3.5%; adjusted odds ratio, 0.24; 95% confidence interval, 0.15–0.38). Term elective induction was not associated with any statistically significant increase in adverse newborn infant outcomes. Elective induction of labor at 39 weeks gestation was associated with increased time from admission to delivery for both nulliparous (1.3 hours; 95% confidence interval, 0.2–2.3) and multiparous women (3.4 hours; 95% confidence interval, 3.2–3.6).
Conclusion
Elective induction of labor at 39 weeks gestation is associated with a decrease in cesarean birth in nulliparous women, decreased pregnancy-related hypertension in multiparous and nulliparous women, and increased time in labor and delivery. How to use this information remains the challenge.
A number of observational studies and systematic reviews have suggested that term induction of labor is not associated with an increase in cesarean birth, may reduce perinatal death and morbidity,
These recent studies importantly compared induction of labor with expectant management of the pregnancy, not simply spontaneous labor, which is the appropriate clinical comparison.
Similarly, systematic reviews of randomized trials beyond the term period (41 and 42 weeks gestation) have found induction of labor to be associated with a lower rate of cesarean birth.
This multicenter cohort study was performed to evaluate outcomes after term elective induction of labor at ≥39 weeks.
Key findings
Nulliparous women who gave birth at 39 weeks gestation after elective induction of labor had decreased odds of cesarean birth, increased odds of operative vaginal birth, and increased time from hospital admission to delivery. Gestational hypertension/preeclampsia was decreased in both electively induced multiparous and nulliparous women. Elective induction at 39 or 40 weeks gestation was not associated with any statistically significant increase in the rate of adverse newborn infant outcomes.
What does this add to what is known?
Our results are consistent with those of the ARRIVE trial that showed a decrease in cesarean birth that is associated with elective induction of labor at 39 weeks gestation in nulliparous women.
In the past 2 years, 2 randomized controlled trials have examined the issue of induction of labor vs expectant management of pregnancy. The 35–39 trial from the United Kingdom reported no increase in the rate of cesarean birth rate in nulliparous women aged 35–39 years who were induced electively at 39 weeks gestation compared with women who were expectantly treated.
The ARRIVE (A Randomized Trial of Induction Versus Expectant Management) trial, which was performed in the United States, reported a decrease in cesarean birth in nulliparous women who were induced electively at 39 weeks gestation.
However, questions have been raised about the applicability of the findings of the ARRIVE trial to the general US population, particularly given the young median age of trial participants, the low rate of cesarean birth, and the hospitals in the Maternal-Fetal Units Network that participated in the study.
The goal of the current study was to compare maternal and newborn infant outcomes in nulliparous and multiparous births at ≥39 weeks gestation that underwent elective induction of labor (induction without a medical indication) compared with pregnancies that were managed expectantly.
Material and Methods
This study used chart-abstracted data on consecutive births from 21 hospitals that participated in a quality initiative in the Northwest United States for all or part of the study period (January 1, 2012, to December 31, 2017). The study was restricted to singleton cephalic hospital births at 39+0–42+6 weeks gestation. Exclusions included previous cesarean birth, cesarean birth without any attempt at vaginal birth, missing data for delivery type or gestational week at birth, antepartum stillbirth, fetal anomaly, gestational diabetes mellitus, prepregnancy diabetes mellitus, and prepregnancy hypertension.
The indication for induction of labor was obtained from a single field in the database. If the indication for induction in this field was recorded as either “Elective” or “Not medically indicated,” then the induction of labor was categorized as “elective” for the purposes of the study. Database abstractors were instructed to categorize induction of labor as “elective” if the indication for induction of labor stated in the medical record was “elective” and to record the indication for induction of labor as “not medically indicated” if the only stated indication for induction in the medical record was any of the following items: history of fast labor, distance from hospital, suspected macrosomia, psychosocial, maternal discomfort, advanced cervical dilation with group B streptococcus negative status, or <41 weeks gestation with no medical indication for induction. Abstractors were directed to the admission history and physical in the medical record to obtain this information. Any induction of labor at ≥41 weeks gestation or ruptured membranes at the time of admission was considered to be indicated medically. There was no further recategorization of “soft indications” to include them in the elective induction group in the study.
The gestational age at birth was based on the clinical estimated date of confinement (EDC) stated in the medical record. Data were collected on whether the EDC was calculated with the use of the last menstrual period, the use of ultrasound scans, the use of other data, or if the source of the EDC was not documented in the medical record. If the EDC was determined with ultrasound scanning, abstractors were instructed to record the gestational age (in weeks) at which this ultrasound scan was performed. The Obstetrical Care Outcomes Assessment Program (OB COAP) did not stipulate how participating sites determined gestational age or whether they followed the American College of Obstetricians and Gynecologists guidelines for determining gestational age, which was the method used to determine gestational age in the ARRIVE trial.
The ARRIVE trial also excluded pregnancies for which the first ultrasound scan was at >20 weeks 6 days gestation. No births were excluded from our study based on the method used to determine EDC.
The primary outcome, cesarean birth, was evaluated for those who gave birth at 39 (39+0–39+6 weeks) and 40 weeks gestation (40+0–40+6 weeks) after elective induction of labor compared with all other pregnancies from the same gestational week that were not induced electively in that week (on-going pregnancies) and delivered either in the same week or future gestational weeks. A sensitivity analysis was also performed to compare cesarean birth rates with the use of a different comparator group: on-going pregnancies in the next or future gestational weeks.
The difference in the median gestational age at birth (in days) was compared between births at 39 and 40 weeks gestation that were induced electively and the respective on-going pregnancies group. Additional secondary maternal outcomes included operative vaginal birth, shoulder dystocia, 3rd- or 4th-degree perineal laceration, pregnancy-related hypertension (preeclampsia or gestational hypertension), and postpartum hemorrhage. Newborn infant outcomes included 5-minute Apgar score <7, intubation at delivery, respiratory complications, macrosomia (birthweight >4500 g), and neonatal intensive care unit (NICU) admission. Respiratory complications included any newborn infant respiratory complication that was recorded in the medical record and were not limited to specific diagnoses or degrees of severity
Bishop score (but not its individual components) was available only for women who underwent elective induction of labor at a subset of participating hospitals and was not provided systematically by all sites. Cervical effacement and dilation at the first cervical examination that was recorded on admission to labor and delivery were available. For women who underwent induction of labor, this first examination reflected a prelabor cervical examination. For women who were not induced, the first cervical examination most likely reflected early or established labor. Cervical dilation was compared for women who underwent elective induction, women who underwent medically indicated induction, and women in spontaneous labor. A sensitivity analysis was performed to understand the impact of dilation at admission on the cesarean birth rate. Mixed effect logistic regression modeling was used to calculate odds ratios for outcomes, with adjustment for maternal age and body mass index. The hospital was included as a random effect to account for possible clustering with the hospital. Adjusted odds ratios with 95% confidence intervals are presented. All models use the on-going pregnancies group as the referent group. Results are stratified by parity and gestational week at birth. Sensitivity analyses were conducted with the use of a subset of hospitals with provider information to assess the extent of clustering within providers by comparing results of the logistic regression models with and without providers included as random effects.
The median time and interquartile range (hours) from admission to delivery, delivery to discharge, and admission to discharge in the mother and the median length of hospital stay for the baby were calculated. These times were compared between elective inductions and on-going pregnancies with the use of the Hodges-Lehmann estimate of the median pairwise distance.
The data for this retrospective cohort study came from the Foundation for Health Care Quality’s OB COAP, which is an on-going multicenter clinician-led, quality improvement collaborative. Clinical data on consecutive births are collected routinely from the medical record and capture a wide range of variables that include maternal demographics, prepregnancy health, pregnancy complications, labor course, birth, and postnatal outcomes for both mothers and babies. OB COAP has been described in detail previously.
Data are entered into a cloud-based, standardized data tool by individually trained abstractors, who include obstetric providers, nurses, and healthcare data and quality improvement specialists. At sites with electronic medical records, selected fields are uploaded directly from the medical record. Data undergo real-time data quality and validation checks that are performed both at the site and at the aggregate level. Ad hoc quality checks are also conducted on a routine basis by OB COAP staff. Monthly data manager educational sessions and unlimited access to OB COAP staff for education and support are available. Volumes submitted to OB COAP are audited annually against billing records with a minimum of 90% agreement required.
The Western Institutional Review Board determined in 2015 that OB COAP is not engaged in human subjects research and does not require institutional review board review.
Results
During the study period, 109,327 singleton term cephalic births were entered into the OB COAP database. After exclusions, a total of 55,694 births were included in the study cohort: 4002 elective inductions and 51,692 expectantly managed births at 39-42+6 weeks gestation (Figure). This led to comparisons of 2318 women with an elective induction of labor at 39 weeks gestation vs 53,376 women who were treated expectantly at ≥39 weeks gestation. Similarly, there were 1684 women at 40 weeks gestation with an elective induction of labor compared with 30,715 women who were treated expectantly.
The mean maternal age was 29.8 years in the 39-week elective induction group and 29.3 years in the group who were not electively induced (Table 1). Elective induction was associated with multiparity, older maternal age, and higher body mass index compared with women who were treated expectantly. In all, 49.1% of the cohort was nulliparous, and 50.9% was multiparous. The cesarean birth rate was 23.2% in nulliparous women and 3.3% in multiparous women. Labor was induced electively in 4002 women or 7.7% of the study cohort.
Table 1Characteristics of the study cohort
Variable
Elective induction at 39 weeks gestation (n=2318), n (%)
On-going pregnancies (n=53,376), n (%)
P value
Elective induction at 40 weeks gestation (n=1684), n (%)
On-going pregnancies (n=30,715), n (%)
P value
Demographic characteristics
Age at admission, y
<.001
<.001
<20
47 (2)
2,344 (4.4)
41 (2.4)
1,324 (4.3)
20–34
1807 (78)
40,972 (76.8)
1280 (76)
23,591 (76.8)
35–39
359 (15.5)
7,764 (14.5)
280 (16.6)
4,505 (14.7)
≥40
83 (3.6)
1,432 (2.7)
66 (3.9)
772 (2.5)
Missing
22 (0.9)
864 (1.6)
17 (1)
523 (1.7)
Race and ethnicity
<.001
<.001
White, non-Hispanic
1534 (66.2)
27,344 (51.2)
1037 (61.6)
16,268 (53)
Black, non-Hispanic
43 (1.9)
1,877 (3.5)
30 (1.8)
1,196 (3.9)
Hispanic
357 (15.4)
8,336 (15.6)
278 (16.5)
4,290 (14)
Asian or Pacific Islander
140 (6)
7,548 (14.1)
147 (8.7)
4,002 (13)
American Indian or Alaska Native
38 (1.6)
616 (1.2)
27 (1.6)
310 (1)
Other
73 (3.1)
2,031 (3.8)
54 (3.2)
1,134 (3.7)
Missing
133 (5.7)
5,624 (10.5)
111 (6.6)
3,515 (11.4)
Health insurance
<.001
<.001
Commercial
1078 (46.5)
25,398 (47.6)
805 (47.8)
14,936 (48.6)
Not commercial
916 (39.5)
18,907 (35.4)
641 (38.1)
10,363 (33.7)
Missing
324 (14)
9,071 (17)
238 (14.1)
5,416 (17.6)
Prepregnancy health
Body mass index, kg/m2
<.001
<.001
<30
1016 (43.8)
24,917 (46.7)
705 (41.9)
13,871 (45.2)
30–39
1017 (43.9)
20,350 (38.1)
751 (44.6)
12,098 (39.4)
≥40
190 (8.2)
3,387 (6.3)
152 (9)
1,983 (6.5)
Missing
95 (4.1)
4,722 (8.8)
76 (4.5)
2,763 (9)
Pregnancy characteristics
Parity
<.001
<.001
Nulliparous
218 (9.4)
27,533 (51.6)
342 (20.3)
17,765 (57.8)
Multiparous
2100 (90.6)
25,843 (48.4)
1342 (79.7)
12,950 (42.2)
Prenatal care: incomplete/absent prenatal care
18 (0.8)
1,102 (2.1)
29 (1.7)
634 (2.1)
.43
Ultrasound dating
Ultrasound-based dating
479 (41.1)
9,032 (34.1)
<.001
321 (39.1)
5,001 (33.4)
<.001
Dating ultrasound <21+0 wk gestation
431(95.8)
7,576 (91.0)
<.001
271 (90)
4,153 (90.1)
<.001
Induction of labor
2318 (100)
14,407 (27.0)
<.001
1684 (100)
9,411 (30.6)
<.001
Epidural
1895 (82.0)
38,407 (72.2)
<.001
1388 (82.6)
22,734 (74.2)
Hospital level of neonatal care
<.001
<.001
I
438 (18.9)
7476 (14)
257 (15.3)
4242 (13.8)
II
204 (8.8)
8880 (16.6)
170 (10.1)
5302 (17.3)
III-IV
1676 (72.3)
37020 (69.4)
1257 (74.6)
21171 (68.9)
Souter et al. Elective induction at term. Am J Obstet Gynecol 2019.
At 39 weeks gestation, the cesarean rate in electively induced nulliparous women was 14.7% vs 23.2% (adjusted odds ratio, 0.61; 95% confidence interval, 0.41–0.89) in expectantly treated nulliparous women (Table 2). At 40 weeks gestation, the cesarean rates that compared elective induction of labor with expectant management were 24.0% vs 26.4% (adjusted odds ratio, 0.90; 95% confidence interval, 0.70–1.17) in nulliparous women. Among multiparous women, there was no statistically significant difference in cesarean rates with elective induction at either 39 or 40 weeks gestation. Results did not appreciably change when the analysis used clustering on providers in the subset of hospitals for which provider identification was available.
Table 2Cesarean birth rates in elective inductions and on-going pregnancies
There was a 5-day difference in the median gestational age at birth for nulliparous women who were induced electively at 39 weeks gestation compared with expectantly managed nulliparous pregnancies. This difference was 4 days in multiparous women.
The sensitivity analysis that was performed with on-going pregnancies in the next gestational week as the comparator group (instead of on-going pregnancies in the same gestational week) showed a statistically significant decrease in cesarean birth at 39 and 40 weeks gestation for nulliparous women who underwent elective induction (Supplemental Table 1). It also showed a statistically significant decrease in cesarean birth at 39 weeks gestation in multiparous women.
Elective induction of labor at 39 weeks gestation was associated with an increase in the rate of operative vaginal birth (forceps or vacuum) in nulliparous women (18.5% vs 10.8%; adjusted odds ratio, 1.8; 95% confidence interval, 1.28–2.54). Term elective induction both at 39 and 40 weeks gestation was also associated with a decrease in hypertensive disorders of pregnancy (preeclampsia/gestational hypertension) irrespective of parity (Table 3). Elective induction at 39 or 40 weeks gestation was not associated with any statistically significant increases in the rates of adverse newborn infant outcomes. Statistically significant decreases were observed for NICU admission in nulliparous women who were induced at 39 weeks gestation, neonatal respiratory complications in nulliparous women who were induced at 40 weeks gestation, and neonatal intubation in multiparous women who were induced at 39 weeks gestation (Table 4).
Table 3Maternal outcomes for elective inductions and on-going pregnancies
Bishop score was available for 43.0% of nulliparous women (241/560) and 55.8% of multiparous women (1921/3442) who were induced electively. For elective inductions with a Bishop score available, the median score was 8 in both nulliparous and multiparous women, and the score was <5 in 15.4% of nulliparous women and 9.1% of multiparous women.
As expected, spontaneously laboring women had greater cervical dilation and effacement on the first cervical examination compared with women who were admitted for induction of labor (Supplemental Table 2). For women who underwent elective induction of labor, median cervical effacement was 75% in nulliparous women and 70% in multiparous women. Median cervical dilation was 3 cm in both nulliparous and multiparous women who underwent elective induction. Women who were induced for a medical indication tended to have less favorable cervical examinations. The sensitivity analysis that adjusted for dilation at admission did not change the estimated odds ratios for cesarean birth materially.
In nulliparous women, elective induction of labor at 39 weeks gestation was associated with an increase in the admission-to-delivery time, a decrease in the delivery-to-discharge time, and a decrease in the total duration of the hospital stay for the mother and the baby (Table 5). For multiparous women, elective induction of labor at 39 and 40 weeks gestation was associated with an increased admission-to-delivery time, a decreased delivery-to-discharge time for the mother, and no statistically significant difference in total length of maternal hospital stay.
The Hodges-Lehmann estimate of the median pairwise distance was used to compare the difference in stay between elective inductions and on-going pregnancies.
At 39 weeks gestation
Nulliparous
Admit to delivery
13.5 (10.1–20.8)
13.0 (8.2–19.6)
1.3
0.2–2.3
<.05
Delivery to discharge (mother)
29.6 (24.5–41.9)
38.8 (29.4–50.3)
–6.5
–3.5 to –9.5
<.001
Total (mother)
45.1 (35.1–67.0)
53.5 (40.9–69.1)
–4.9
–9.3 to –0.9
<.05
Total (baby)
30.2 (24.7–42.8)
40.2 (30.1–52.8)
–7.2
–4.2 to –10.5
<.001
Multiparous
Admit to delivery
9.2 (7.0–12.5)
6.0 (3.0–10.1)
3.4
3.2–3.6
<.001
Delivery to discharge (mother)
25.9 (23.6–36.0)
29.8 (25.3–37.3)
–2.5
–2.9 to –2.0
<.001
Total (mother)
35.7 (31.7–48.8)
36.6 (31.4–46.1)
0.4
–0.2–0.9
.24
Total (baby)
26.2 (23.8–37.6)
30.5 (25.4–38.7)
–2.6
–3.1 to –2.1
<.001
At 40 weeks gestation
Nulliparous
Admit to delivery
14.4 (11.1–19.3)
14.0 (9.0–20.8)
0.8
0.0–1.6
.06
Delivery to discharge (mother)
39.1 (27.7–49.2)
39.3 (29.8–51.3)
–1.7
–4.0–0.5
.13
Total (mother)
54.9 (45.2–71.0)
54.9 (42.0–71.3)
0.2
–2.8–3.2
.91
Total (baby)
41.4 (29.7–51.6)
40.8 (30.6–53.7)
–1.2
–3.6–1.3
.33
Multiparous
Admit to delivery
9.5 (7.1–12.7)
6.3 (3.2–10.6)
3.2
3.0–3.5
<.001
Delivery to discharge (mother)
25.8 (23.4–35.6)
29.9 (25.2–37.3)
–2.7
–3.2 to –2.1
<.001
Total (mother)
35.5 (31.7–47.7)
36.9 (31.6–47.0)
–0.2
–0.9–0.5
.61
Total (baby)
26.1 (23.7–38.0)
30.5 (25.4–38.7)
–2.6
–3.2 to –2.0
<.001
Souter et al. Elective induction at term. Am J Obstet Gynecol 2019.
a The Hodges-Lehmann estimate of the median pairwise distance was used to compare the difference in stay between elective inductions and on-going pregnancies.
our study suggests that elective induction of labor at 39 weeks gestation is associated with a decrease in cesarean birth for nulliparous women and a decrease in pregnancy-related hypertension for both nulliparous and multiparous women. Induction of labor at 39 weeks gestation was associated with a statistically significant increase in the time in labor and delivery for both multiparous and nulliparous women, but a decrease in the total hospital stay for nulliparous women.
Although our study showed an association between term elective induction and decreased risk for hypertensive disorders of pregnancy in multiparous women, it did not show an association between term elective induction of labor and cesarean birth in multiparous women when compared with on-going pregnancies in the same gestational week. This finding is important because most recent studies have focused on nulliparous women; our study suggests that the implications of term elective induction for mode of delivery are different, dependent on parity.
Strengths and weaknesses
Although our study does potentially deal with some of the issues of concern in the ARRIVE trial, such as the inclusion of nonacademic community hospitals, the study has several limitations. As a retrospective cohort study, the issue of confounding bias is impossible to eliminate, even with multivariable statistical techniques. The 14.7% cesarean birth rate and the relatively low median time on labor and delivery (13.5 hours) for nulliparous women who underwent elective induction at 39 weeks gestation suggest that there may have been factors in the elective induction group (eg, favorable outpatient Bishop score) that could have lowered the threshold for induction and in turn have increased the likelihood of vaginal birth. Although we were able to evaluate a range of maternal and newborn infant outcomes, we do not have data on the indication for admission to the NICU, the severity of respiratory complications, or respiratory diagnoses. Additionally, we could not control for variation in provider practices that could have led to different treatment approaches in women who were induced electively compared with women who were not. However, we did conduct the analysis clustering by provider and did not find any significant changes in the outcomes. It is also noted that our study captured only short-term maternal and newborn infant outcomes and that the long-term implications of term elective induction of labor are unknown.
Comparison of the findings of the current study with those of previous studies
Our study findings are consistent with previous studies that used the methodologic approach of induction of labor vs expectant management and that found lower rates of cesarean delivery and perinatal complications with elective induction of labor. However, our study differs from many of the previous retrospective cohort studies of term elective induction of labor in several ways. The data were extracted directly from the medical record rather than from routinely collected/administrative data such as that used by others.
Additionally, the elective induction group in our study was identified through the indication for induction of labor in the medical record, rather than by the presence of induction of labor in the absence of any discernable medical indication for induction or contraindication to induction.
We were also able to exclude cesarean births (both scheduled and emergency) where there was no attempt at vaginal birth.
Aside from the obvious inclusion of multiparous and nulliparous women, the current study population differed from that of the ARRIVE trial in a number of ways. In our study population, the mean maternal age was greater (29 years); the births were at level I, II, and III-IV hospitals with no unifying policy on induction of labor, and there were higher rates of Asian and white women and fewer black and Hispanic women, which suggests that the findings of the ARRIVE trial are potentially applicable to a wider population.
Clinical implications
The question remains as to what to do with this information. For women who are concerned about the risks of prolonging pregnancy to >39 weeks gestation, elective induction seems to be a reasonable option and does not appear to increase the cesarean delivery rate. It may also have favorable impacts on some other maternal and newborn infant outcomes, although the possibility of unintended consequences for the mother and baby that we have not considered or measured cannot be excluded. At a population level, though, offering routine elective induction of labor is likely not feasible. Such a process potentially would lead to overcrowded labor and delivery units that may not have adequate space or staffing for patients with medical complications of pregnancy. Additionally, our study and the ARRIVE trial both demonstrated an increased amount of time on labor and delivery for the women who underwent elective induction. This likely would lead to increased costs; therefore, the economic impact of term elective induction needs further evaluation.
In addition, despite the finding of lower cesarean birth rates, routine elective induction of labor at 39 weeks gestation may not be a practical strategy for the reduction of the cesarean birth rate. The ARRIVE trial suggested that 1 cesarean birth may be avoided for every 28 births in low-risk nulliparous women who are planning elective induction of labor at 39 weeks gestation. However, considering the increase in the rate of induction of labor in singleton pregnancies from approximately 10% in 1990 to 26% in 2017 and the concurrent increase in the cesarean birth rate from approximately 22–32%, it is questionable whether further increases in the frequency of induction alone are likely to decrease the cesarean birth rate significantly.
It is also uncertain how most consumers of maternity care feel about elective induction of labor. Physiologic birth is ranked highly in international studies about what women want for childbirth
; in a survey from California that reported results from 2539 women who had recently given birth in hospital, 74% of the women agreed with the statement that “childbirth is a process that should not be interfered with unless medically necessary.”
For such individuals, even a routine offering of elective induction of labor may feel coercive from the medical establishment. Thus, it is imperative for providers to understand patient preferences regarding not only mode of delivery but also of interventions in pregnancy.
Elective induction at 39 weeks gestation adds to the growing number of optional interventions in pregnancy. These interventions may be very beneficial for some, add unnecessary intervention and risk for others, and require considerable resources in an already expensive healthcare system. More accurate assessment of risk and benefits of interventions for individuals, rather than the population as a whole, may be the way forward in supporting women in their choices for childbirth. Additional assessment of the impact and outcomes of this intervention in a range of settings and the economic impact are imperative before elective induction of labor becomes offered routinely.
Appendix
Supplemental Table 1Cesarean birth rates in elective inductions and “on-going pregnancies” in the next gestational week (births in the next gestational week and beyond)
Cesarean birth
Week at birth
Elective inductions, %
On-going pregnancies in the next gestational week, %
The Foundation for Health Care Quality is a 501(c)(3) non-profit organization supported by membership dues from the participants in its programs.
The authors report no conflict of interest.
Cite this article as: Souter V, Painter I, Sitcov K, et al. Maternal and newborn outcomes with elective induction of labor at term. Am J Obstet Gynecol 2019;220:273.e1-11.
Souter et al1 have presented a careful and comprehensive evaluation of outcomes after elective induction of labor compared with expectant management. These authors have joined the ranks of others who offer labor induction at 39 weeks gestation as a favorable alternative to expectant management. An explanation for the findings of these groups is that expectant management is associated with a higher prevalence of preeclampsia and with larger babies, which are findings that were confirmed in the ARRIVE trial.
We appreciate Dr Scialli’s thoughtful comments about our study on elective induction of labor (IOL) at term and his concerns about current obstetric practices that contribute to high rates of intervention in births beyond 39 gestational weeks.1
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