39-Week nulliparous inductions are not elective

Impact of the ARRIVE Trial on Stillbirth Rates in Nulliparous Individuals

OBJECTIVE

 We aim to examine the population-level rates of induction, stillbirth, perinatal mortality, and neonatal death before and after the ARRIVE (A Randomized Trial of Induction Versus Expectant Management) trial.

STUDY DESIGN

 This study was a cross-sectional analysis of publicly available U.S. Live Birth data linked with Infant Death and Fetal Death certificate data from National Vital Statistics Online. We limited analyses to nulliparous individuals with singleton pregnancy and cephalic presentation who delivered at 39 weeks or greater. The pre- and post-ARRIVE periods spanned from August 2016 to July 2018, and from January 2019 to December 2020, respectively. Our primary outcome was a stillbirth. Secondary outcomes included induction of labor, perinatal mortality, and neonatal death. Outcomes were compared between the pre- and post-ARRIVE periods. Modified Poisson regression was used to calculate adjusted relative risks (aRRs).

RESULTS

 Of 2,817,071 births, there were 1,454,346 births in the pre-ARRIVE period and 1,362,725 in the post-ARRIVE period; there were 1,196 and 1,062 stillbirths in the pre- and post-ARRIVE periods, respectively. Compared to the pre-ARRIVE period, the post-ARRIVE period was not associated with a significant decrease in the risk of stillbirth at 39 weeks or greater (aRR = 0.92 [95% confidence interval (95% CI): 0.85-1.00]) and stillbirth at 40 weeks or greater (aRR = 0.92 [95% CI: 0.82-1.04]). Compared to the pre-ARRIVE trial period, the post-ARRIVE trial was associated with increased rates of induction of labor at 39 weeks (aRR = 1.37 [95% CI: 1.37-1.38]) and 40 weeks (aRR = 1.24 [95% CI: 1.24-1.25]. Similar to stillbirth, there was no significant decrease in the risk of perinatal mortality at 39 weeks or greater or 40 weeks or greater. There was also no statistically significant change in neonatal death rates at 39 weeks or greater or at 40 weeks or greater.

CONCLUSION

 The increase in induction of labor at 39 weeks was not large enough to impact the stillbirth rate at 39 weeks or greater.

KEY POINTS

· Post-ARRIVE trial, rate of induction of labor increased at 39 and 40 weeks.. · Post-ARRIVE trial, stillbirth and perinatal mortality rates remained unchanged.. · Induction rate rise post-ARRIVE trial did not impact neonatal death rates..

The role of labor induction in modern obstetrics

A primary goal of obstetrical practice is the optimization of maternal and perinatal health. This goal translates into a seemingly simple assessment with regard to considerations of the timing of delivery: delivery should occur when the benefits are greater than those of continued pregnancy. In the absence of an indication for cesarean delivery, planned delivery is initiated with induction of labor. When medical or obstetrical complications exist, they may guide recommendations regarding the timing of delivery. In the absence of these complications, gestational age also has been used to guide delivery timing, given its association with both maternal and perinatal adverse outcomes. If there is no medical indication, delivery before 39 weeks has been discouraged, given its association with greater chances of adverse perinatal outcomes. Conversely, it has been recommended that delivery occur by 42 weeks of gestation, given the perinatal risks that accrue in the post-term period. Historically, a 39-week induction of labor, particularly for individuals with no previous birth, has not been routinely offered in the absence of medical or obstetrical indications. That approach was based on numerous observational studies that demonstrated an increased risk of cesarean delivery and other adverse outcomes among individuals who underwent labor induction compared to those in spontaneous labor. However, from a management and person-centered-choice perspective, the relevant comparison is between those undergoing planned labor induction at a given time vs those planning to continue pregnancy beyond that time. When individuals have been compared using that rubric-either in observational studies or randomized trials that have been performed in a wide variety of locations and populations- there has not been evidence that induction increases adverse perinatal or maternal outcomes. Conversely, even when the only indication for delivery is the achievement of a full-term gestational age, evidence suggests that multiple different outcomes, including cesarean delivery, hypertensive disorders of pregnancy, neonatal respiratory impairment, and perinatal mortality, are less likely when induction is performed. This information underscores the importance of making the preferences of pregnant individuals for different birth processes and outcomes central to the approach to delivery timing.

The impact of birth settings on pregnancy outcomes in the United States

In the United States, 98.3% of patients give birth in hospitals, 1.1% give birth at home, and 0.5% give birth in freestanding birth centers. This review investigated the impact of birth settings on birth outcomes in the United States. Presently, there are insufficient data to evaluate levels of maternal mortality and severe morbidity according to place of birth. Out-of-hospital births are associated with fewer interventions such as episiotomies, epidural anesthesia, operative deliveries, and cesarean deliveries. When compared with hospital births, there are increased rates of avoidable adverse perinatal outcomes in out-of-hospital births in the United States, both for those with and without risk factors. In one recent study, the neonatal mortality rates were significantly elevated for all planned home births: 13.66 per 10,000 live births (242/177,156; odds ratio, 4.19; 95% confidence interval, 3.62-4.84; P<.0001) vs 3.27 per 10,000 live births for in-hospital Certified Nurse-Midwife-attended births (745/2,280,044; odds ratio, 1). These differences increased further when patients were stratified by recognized risk factors such as breech presentation, multiple gestations, nulliparity, advanced maternal age, and postterm pregnancy. Causes of the increased perinatal morbidity and mortality include deliveries of patients with increased risks, absence of standardized criteria to exclude high-risk deliveries, and that most midwives attending out-of-hospital births in the United States do not meet the gold standard for midwifery regulation, the International Confederation of Midwives' Global Standards for Midwifery Education. As part of the informed consent process, pregnant patients interested in out-of-hospital births should be informed of its increased perinatal risks. Hospital births should be supported for all patients, especially those with increased risks.

Novel Evidence-Based Labor Induction Algorithm Associated with Increased Vaginal Delivery within 24 Hours

OBJECTIVE

This study aimed to assess whether concordance with our proposed labor induction algorithm is associated with an increased rate of vaginal delivery within 24 hours.

STUDY DESIGN

We conducted a retrospective review of 287 induction of labors (IOLs) at a single urban, tertiary, academic medical center which took place before we created an evidence-based IOL algorithm. We then compared the IOL course to the algorithm to assess for concordance and outcomes. Patients age 18 years or over with a singleton, cephalic pregnancy of 36^6/7 to 42^0/7 weeks' gestation were included. Patients were excluded with a Bishop's score >6, contraindication to misoprostol or cervical Foley catheter, major fetal anomalies, or intrauterine fetal death. Patients with 100% concordance were compared with <100% concordant patients, and patients with ≥80% concordance were compared with <80% concordant patients. Adjusted hazard ratios (AHRs) were calculated for rate of vaginal delivery within 24 hours, our primary outcome. Competing risk's analysis was conducted for concordant versus nonconcordant groups, using vaginal delivery as the outcome of interest, with cesarean delivery (CD) as a competing event.

RESULTS

Patients with 100% concordance were more likely to have a vaginal delivery within 24 hours, n = 66 of 77 or 85.7% versus n = 120 of 210 or 57.1% (p < 0.0001), with an AHR of 2.72 (1.98, 3.75, p < 0.0001) after adjusting for delivery indication and scheduled status. Patients with 100% concordance also had shorter time from first intervention to delivery (11.9 vs. 19.4 hours). Patients with ≥80% concordance had a lower rate of CD (11/96, 11.5%) compared with those with <80% concordance (43/191 = 22.5%; p = 0.0238). There were no differences in neonatal outcomes assessed.

CONCLUSION

Our IOL algorithm may offer an opportunity to standardize care, improve the rate of vaginal delivery within 24 hours, shorten time to delivery, and reduce the CD rate for patients undergoing IOL.

KEY POINTS

· Studies on IOL have focused on individual steps. A labor induction algorithm allows for standardization.. · Algorithm concordance is associated with decreased time to delivery.. · Algorithm concordance is associated with decreased CD rate..

Misoprostol for labour induction

Oral and vaginal misoprostol are effective induction methods, but there is a delicate balance between a quicker labour and avoiding side effects. In randomised comparisons with balloon catheters, oral misoprostol resulted in more vaginal births in the first 24 h as well as fewer caesarean sections without an increase in hyperstimulation events. Vaginal misoprostol was most effective when used concurrently with a balloon catheter. In comparison with dinoprostone, oral misoprostol had lower rates of caesarean section and uterine hyperstimulation with foetal heart rate changes, but fewer babies were born vaginally within 24 h. In contrast, vaginal misoprostol resulted in more vaginal births within 24 h, with no significant differences in caesarean section rates. There were no differences in perinatal adverse events with either route. When oral and vaginal misoprostol were compared, vaginal misoprostol resulted in more vaginal births in the first 24 h, but with more maternal and neonatal complications.

Outpatient labour induction

The inexorable rise in induction rates over the past two decades, in parallel with increasing medical costs and pressure to reduce length of stay, has led to marked logistic difficulties for health care workers, managers and planners. Maternity services are being overwhelmed by the need to allocate staff and delivery suite space for the scheduling and undertaking of induction processes, rather than focussing care for women in spontaneous labour. Induction of labour according to the majority of current protocols and guidelines necessitates increased length of stay and relatively aggressive use of oxytocin (to reduce the time expended in the labour ward from artificial rupture of membranes (AROM) to establishment of labour). This increased oxytocin usage requires increased use of continuous electronic foetal monitoring, and may also increase epidural usage, further increasing the complexity of labour for the woman and her health care workers. Outpatient care after cervical priming and even outpatient care after AROM may help to ease these pressures and may reduce the medicalisation of the birth experience when induction is indicated, with a potential to reduce oxytocin use and associated interventions. If the period between cervical priming to AROM is managed as outpatient care, then the woman may be able to find better psychological and social support at home, as well as maintain autonomy and get better rest prior to the onset of labour. Inpatient AROM could also be followed by outpatient care until the pregnant person returns to the hospital, either in spontaneous labour, or for initiation of syntocinon after 12-18 h. High-quality research has already demonstrated that outpatient care for cervical ripening is acceptable to mothers and caregivers, has economic benefits and has an acceptable safety profile in appropriately selected low-risk inductions.

Induction of labour in low-resource settings

Due to the disparity in resource availability between low- and high-resource settings, practice recommendations relevant to high-income countries are not always relevant and often need to be adapted to low-resource settings. The adaptation applies to induction of labour (IOL) which is an obstetric procedure that deserves special attention because it involves the initiation of a process that requires regular and frequent monitoring of the mother and foetus by experienced healthcare professionals. Lack of problem recognition and/or substandard care during IOL may result in harm with long-term sequelae. In this article, the authors discuss unique challenges such as insufficient resources (including staff, midwives, doctors, equipment, and medications) that result in occasional inadequate patient monitoring and/or delayed interventions during IOL in low-resource settings. We also discuss modifications in indications and methods for IOL, issues related to human immunodeficiency virus (HIV) infections, the feasibility of outpatient induction, clinical protocols and a minimum dataset for quality improvement projects. Overall, the desire to achieve a vaginal birth with IOL should not cloud the necessity to observe the required safety measures and implement necessary interventions; given that childbirth practices are the major determinants of pregnancy outcomes and patient satisfaction.