By Mitchell Linder, MD
Assistant Professor, Department of Obstetrics and Gynecology, University of Rochester School of Medicine and Dentistry, Strong Memorial Hospital, Rochester, NY
Dr. Linder reports no financial relationships relevant to this field of study.
SYNOPSIS: In this randomized controlled trial among nulliparous patients with low Bishop scores, outpatient placement of a Foley catheter the day prior to scheduled admission, when compared to inpatient placement, showed a decreased mean time from admission to delivery.
SOURCE: Ausbeck EB, Jauk VC, Xue Y, et al. Outpatient Foley catheter for induction of labor in nulliparous women: A randomized controlled trial. Obstet Gynecol 2020;136:597-606.
This randomized controlled trial compared outpatient placement of a Foley catheter on the day prior to scheduled admission to scheduled induction patients who received the catheter on admission to the hospital. Women were eligible for the study if they were nulliparous, 18 years of age or older with singleton pregnancies between 39.0 to 41.6 weeks gestation (as determined by a dating ultrasound prior to 20.6 weeks) with planned inductions scheduled, and had modified Bishop scores less than 5 with a maximum cervical dilation of 2 cm.
In addition, participants had to have access to reliable transportation and a telephone and live within 30 minutes of the study hospital. Exclusion criteria included fetal death, fetal anomalies (as defined by the presence of a major anomaly of any organ system), fetal growth restriction, suspected fetal macrosomia, oligohydramnios, polyhydramnios, non-reassuring fetal status (biophysical profile of 6/10 or less on testing done just prior to randomization), prior uterine surgery involving the myometrium, uncontrolled hypertension, uncontrolled pregestational diabetes, White classification type C diabetes or higher, infection with hepatitis B or C or human immunodeficiency virus, latex allergy, or other conditions deemed by the attending physician to be unsuitable for outpatient cervical ripening.
Once enrolled, patients were seen in the office at 39.0 weeks or greater and underwent a biophysical profile, blood pressure evaluation, and a cervical examination. Randomization occurred in a 1:1 fashion. Women randomized to outpatient ripening had a 16 French Foley catheter placed immediately after randomization. The Foley was filled with 30 mL of sterile water and the catheter was placed on tension, taped to the patient’s inner thigh. The women then underwent electronic fetal and contraction monitoring for at least 20 minutes. If the patient was not found to have regular, painful contractions, or bleeding, and if the tracing showed reassuring status, she was discharged home with labor precautions. The patients randomized to inpatient placement were sent home immediately after randomization. All women were admitted the next day for scheduled induction regardless of the group to which they were randomized. Patients randomized to inpatient placement had their catheters inserted on admission. The primary outcome was the total duration of time from hospital admission to delivery.
One hundred twenty-six women were enrolled between May 2018 and October 2019 at the University of Alabama at Birmingham Hospital. One hundred eighteen (94%) of enrolled patients underwent successful catheter placement. The average age for both groups was 22 years. The mean starting gestation was 39.3 weeks. The group demographics were balanced regarding race, education level, public vs. private insurance, tobacco use, and starting modified Bishop score. The only differences were a lower average body mass index and Group B Streptococcus colonization rate in the outpatient cohort.
In reference to the primary outcome, the outpatient catheter group spent less time in the hospital before delivery (17.4 ± 7.4 hours vs. 21.7 ± 9.1 hours), with a mean difference of 4.3 hours (P < 0.01). The proportion of patients delivering within 24 hours of hospital admission also was higher in the outpatient group (81% vs. 65%, P = 0.4). The overall length of stay did not differ between the groups (3.3 days vs. 3.5 days, P = 0.27). Patients in the outpatient group also were more likely to show up in labor prior to their scheduled induction time (22% vs. 5%, P < 0.01). Despite this, the rate of spontaneous rupture of membranes prior to admission was not significantly different between the groups (11% vs. 16%, P = 0.43).
Regarding secondary outcomes, patients who had outpatient placement were found to have higher modified Bishop scores on arrival to the hospital, with values of 3 vs. 1 (P < 0.01) as a result of changes in components of cervical dilation and effacement (3 cm vs. 1 cm, P < 0.1, and 50% effacement vs. 25%, P < 0.01). Women who had outpatient ripening also were found to require lower doses of oxytocin (17.5 vs. 22.6 mU/min, P < 0.01) as well as a shorter time of oxytocin infusion (15.8 h vs. 19.4 h, P < 0.01) and a shorter duration of neuraxial anesthesia use (11.4 h vs. 15 h, P < 0.01). No difference was found in the rates of cesarean delivery, operative delivery, meconium-stained amniotic fluid, duration of rupture of membranes, postpartum hemorrhage, or endometritis. The rate of chorioamnionitis was 22% in the outpatient group and 13% in the inpatient group, but this was not statistically significant (P = 0.16). Outpatient ripening also was found not to be associated with an increase in adverse neonatal outcomes. Patients in both groups were found to be satisfied overall with their care, with no significant differences between scores on patient surveys.
According to the Centers for Disease Control and Prevention, in 2018, 31.9% of all babies in the United States were born via cesarean delivery.1 In that same year, the ARRIVE trial showed that induction of nulliparous women with unfavorable Bishop scores at 39 weeks resulted in lower rates of cesarean surgeries and hypertensive disorders of pregnancy.2 Given these findings, there is a potential for a paradigm shift away from expectant management of these patients. The issue then becomes one of timing, resources, and physical space to care for a potential increased amount of inductions. This study looked at a possible outpatient intervention that could help decrease the use of inpatient hospital resources by way of a safe, relatively inexpensive method.
The authors found positives in the fact that the outpatient ripening decreased the total time from admission to delivery by more than four hours and increased the rate of unscheduled hospital admission without significantly increasing adverse neonatal outcomes, rates of infection, or operative deliveries. They acknowledged that even though an outpatient visit for catheter placement would increase the amount of time and care given to the patient, in the context of healthcare costs, the reduction in hospital use signified that their results were meaningful. They also pointed to the fact that both patient groups scored similarly on their satisfaction surveys to demonstrate that patients ultimately did not seem to mind the extra visit.
In my institution, we have not yet fully embraced the ARRIVE trial’s findings and, thus, many of our groups still are managing patients at or post-term expectantly. If we were to move to actively promote most of our inductions at 39 weeks gestation, I think this research would be a good initial step to help reduce the burden that would come with an increase in potentially lengthy nulliparous inductions. Ideally, I would like to see this research repeated in multiparous patients to see how generalizable it would be to a full practice setting.
- Martin JA, Hamilton BE, Osterman MJ, Driscoll AK. Births: Final data for 2018. Natl Vital Stat Rep 2019;68:1-47.
- Grobman WA, Rice MM, Reddy UM, et al. Labor induction versus expectant management in low-risk nulliparous women. N Engl J Med 2018;379:513-523.