Inclusion and exclusion criteria for outpatient CR
Outpatient CR should be limited to low-risk women with a singleton gestation, who have reliable access to transportation from home to the labor unit and have a clear understanding of the instructions for outpatient CR. Patient characteristics that may be utilized to offer office-based CR include:
- singleton pregnancy at 39 weeks’ and 0 days’ gestation through 40 weeks’ and 6 days’ gestation
- cephalic presentation
- Bishop score ≤6.
Women who should be excluded from outpatient CR include those with:
- contraindications to vaginal delivery
- fetal growth restriction
- abnormal umbilical artery Doppler results
- oligo- or polyhydramnios
- multiple gestation
- major fetal anomaly
- recent nonreactive fetal heart rate tracing
- maternal report of decreased fetal movement
- abnormal biophysical profile
- prior cesarean delivery
- recent vaginal bleeding
- gestational diabetes requiring medication treatment
- significant hypertension.
Practices should establish their own inclusion and exclusion criteria for ambulatory CR.
Safety of office-based ambulatory CR among low-risk women
Safety is a complex concept with experts often disagreeing on what level of safety is required to accept a new medical procedure. Establishing the safety of office-based ambulatory CR among low-risk women would require a very large cohort or randomized studies with at least a thousand participants. Only a few large studies focused on the safety of CR have been reported. Sciscione and colleagues reported a large observational study of inpatient transcervical Foley catheter for CR involving 1,905 women.31 They reported no adverse outcomes among term, singleton, uncomplicated pregnancies. They calculated that the 95% confidence interval (CI) for an adverse event was between 0.0% and 0.2%. In a meta-analysis of 26 studies including 5,563 women, the risk of chorioamnionitis during IOL was equivalent with pre-IOL Foley catheter CR (7.2%) or prostaglandin CR (7.2%) (relative risk, 0.96; 95% CI, 0.66–1.38).32
Two systematic reviews have reported that, compared with balloon CR, misoprostol CR is associated with an increased risk of uterine tachysystole.33-34 In a large retrospective study, compared with inpatient CR, outpatient CR with dinoprostone vaginal insert was not associated with an increased risk of newborn admission to the neonatal intensive care unit or a low Apgar score at 5 minutes after birth.35
Will you consider office-based CR in your obstetric practice?
As reviewed in this editorial, evolving data suggest that it is feasible to initiate CR in the office ambulatory setting prior to admission to the labor unit for additional CR or IOL. Many women prefer to complete CR at home after initiation in the office, rather than have CR in a labor unit or hospital setting.36 The transcervical balloon catheter has the most published data supporting the feasibility of ambulatory CR. Compared with misoprostol, the transcervical balloon catheter is associated with a low rate of uterine tachysystole. It may be a preferred method for outpatient CR. If placement of a transcervical balloon catheter is challenging, for example when the patient has a tightly closed cervix, oral misoprostol ambulatory CR may be an option if CTG monitoring is available in the office.
During the COVID pandemic, many in-person office visits have transitioned to virtual visits with the patient in their home. Historically, most cases of CR have been performed on labor and delivery units. It may be time for your practice to consider office-based ambulatory CR for low-risk women planning an IOL. Office-based ambulatory CR is a win for labor nurses who generally prefer to manage laboring patients rather than patients undergoing prolonged in-hospital CR. Outpatient CR is also a win for low-risk patients who prefer to be at home rather than in a labor unit. ●
