Background: The Patient-Centered Outcomes Research Institute (PCORI) is partnering with AHRQ to develop a systematic evidence review on cervical ripening in the outpatient setting. The American College of Obstetrics and Gynecology (ACOG) plans to update its related clinical guidelines.
Emerging issues in the field: Induction of labor (IOL) has risen dramatically over the last 20 years and is at an historic high approaching 25% of pregnancies in the United States1 and exceeding 30% in the United Kingdom (UK).2 Rates are anticipated to continue to rise,3 in part as a consequence of the findings from the ARRIVE study (2018), a large randomized clinical trial which recently reported that IOL at 39 weeks compared to expectant management was associated with significantly lower rates of cesarean section and no increase in composite adverse events in low-risk nulliparous women.4 Prior to ARRIVE, the obstetrics and gynecology community agreed that the risk of continuing a pregnancy only outweighed maternal/fetal risk associated with delivery before 40 weeks of gestation if there was a clear medical indication.5-9
Women with an unfavorable cervix routinely undergo cervical ripening (CR) as the first, and often lengthy step, in the process of IOL.6 CR usually includes administration of pharmacologic (prostaglandins) or mechanical (Foley catheter) agents that soften, efface or dilate the cervix in order to prepare for vaginal delivery.9
Outpatient CR has been adopted in Canada9 and the United Kingdom (UK),8,10,11 and is being discussed as an option in the United States.3,12 Purported advantages of outpatient CR include a shorter period of hospitalization,13 thereby alleviating resources and space burden to delivery wards,3 and an improved patient experience.3,14 Consequently, implementation of outpatient CR in the United States may be attractive provided it is safe.
Variation exists in methods used for outpatient CR, with the Foley catheter suggested as more advantageous by North American clinicians because of it does not increase risk of uterine hyperstimulation.3,6,9 In contrast, a recent survey of practices of outpatient CR found mechanical methods were not used in the UK10 (National Institute for Health and Care Excellence (NICE) does not recommend mechanical methods for routine IOL due to possible increased risk of infection).8 Instead, UK clinicians preferred slow release prostaglandins,10 even though prostaglandins have been widely associated with an increased risk of tachysystole with fetal heart rate changes.15 Despite juxtaposing North American–UK views, it is noteworthy that two Cochrane systematic reviews were inconclusive as to whether any agent used for outpatient CR has had more favorable impacts on maternal or fetal health,16,17 a result the investigators attribute to a paucity of evidence at the time the review was completed.
Current guidance on outpatient CR is limited and requires updating.6 Although not elevated to a formal clinical recommendation, the text from ACOG Practice Bulletin 107 in 2009 says that "outpatient [CR] may be appropriate in carefully selected patients" and "mechanical methods may be particularly appropriate in the outpatient setting." UK guidance is similarly vague, and outpatient cervical ripening was not addressed by WHO in their 2011 guidance.7
This proposed review will inform ACOG's clinical practice guidelines on outpatient cervical ripening and integrating information on its effectiveness, harms and patient preferences. In addition, the review seeks to understand what options are available for monitoring fetal wellbeing in the outpatient setting, a topic not previously undergone systematic review; and to understand methods of CR appropriate for women experiencing fetal demise, which was last reviewed in 2010.18
Draft Key Questions
- KQ1: What are the effectiveness and potential harms of CR in the outpatient compared to the inpatient setting?
- KQ1a: How does effectiveness and potential harms vary by choice of CR agent (Foley catheter, prostaglandins, etc.)?
- KQ1b: Do effectiveness and potential harms vary by important patient characteristics (such as gestational age, parity, uncomplicated pregnancy, prior cesarean delivery, etc.)?
- KQ2: What are the comparative effectiveness and potential harms of different methods of CR evaluated in the outpatient setting (Foley catheter, prostaglandins, etc.)?
- KQ2a: Does effectiveness and potential harms vary by subgroups defined by gestational age and important patient characteristics (such as gestational age, parity, uncomplicated pregnancy, prior cesarean delivery, etc.)?
- KQ3: What evidence informs preference for or tolerability of different methods of CR in the outpatient setting or outpatient compared to the inpatient setting?
- KQ4: What are the effectiveness and potential harms of available methods for fetal surveillance in pregnant women undergoing CR with prostaglandins in the inpatient and outpatient setting?
- KQ5: What are the effectiveness and potential harms of CR among women presenting with fetal demise in the late second or third trimester, in the inpatient and outpatient setting?
- KQ5a: How do the effectiveness and potential harms of methods of CR compare to one another and to expectant management?
- KQ5b: How do the effectiveness and potential harms of methods of CR vary by gestational age (second versus third trimester) or other important patient characteristics?
Table 1: PICOTS for a systematic review of cervical ripening in the outpatient setting
|KQ1: Inpatient vs. Outpatient||KQ2: Outpatient CR||KQ3: Tolerability, CR Agents||KQ4: Fetal Surveillance||KQ5: Fetal Demise|
|Population||Pregnant women ≥37 wk undergoing CR||Pregnant women ≥37 wk undergoing CR||Pregnant women ≥37 wk undergoing CR||Pregnant women ≥37 wk CR with prostaglandins||Fetal demise, 2nd/3rd trimester undergoing CR|
|Interventiona||CR, inpatient setting||Method of CR||
||Method of fetal surveillance||Method of CR|
|Comparatora||CR, outpatient setting||Expectant management, no treatment or placebo, other CR methods||
||No fetal monitoring or another method of fetal surveillance||Expectant management, no treatment or placebo, other CR methods|
|Outcomesb||Maternal & infant health outcomesc
Maternal & infant mortality and morbidityd
|Maternal & infant health outcomesc
Maternal & infant mortality and morbidityd
|Preference & tolerability||Maternal & infant health outcomesc
Maternal & infant mortality and morbidityd
|Maternal health outcomesc
Maternal & mortality and morbidityd
|Timing||Follow-up not limited||Follow-up not limited||Follow-up not limited||Follow-up not limited||Follow-up not limited|
|Setting||Inpatient & Outpatient||Outpatient||Inpatient & outpatient||Inpatient & outpatient||Inpatient & outpatient|
Consider cohorts for harms
Consider cohort for harms
- Consider inclusion/exclusion of studies of nonstandard treatments, such as castor oil.
- Exclude studies that do not report any outcome of interest.
- Maternal and infant health outcomes include but are not limited to: vaginal delivery 24 hours, successful, vaginal delivery, cesarean delivery, failed induction rate, NICU admission, induction to delivery time, Apgar scores, maternal satisfaction/tolerability.
- Maternal and infant mortality and morbidity includes but not limited to: tachysystole, with or without fetal heart rate changes, postpartum hemorrhage, discomfort/tolerability, uterine rupture, fetal morbidity (FHR changes), fetal and maternal mortality.
- Teitler JO, Plaza R, Hegyi T, Kruse L, Reichman NE. Elective Deliveries and Neonatal Outcomes in Full-Term Pregnancies. American journal of epidemiology. 2019;188(4):674-83.
- NHS Digital. Maternity Statistics 2017-2018. [online] 2018.
- Levine LD, Sciscione AC. Foley Catheter for Outpatient Cervical Ripening: Review of the Evidence and a Proposed Model of Care. Am J Perinatol. 2019.
- Grobman WA, Rice MM, Reddy UM, Tita ATN, Silver RM, Mallett G, et al. Labor Induction versus Expectant Management in Low-Risk Nulliparous Women. The New England journal of medicine. 2018;379(6):513-23.
- ACOG Practice Advisory: Clinical guidance for integration of the findings of The ARRIVE Trial: Labor Induction versus Expectant Management in Low-Risk Nulliparous Women. 2018.
- American College of Obstetricians and Gynecologists (ACOG). ACOG Practice Bulletin No. 107: Induction of labor. Obstetrics and gynecology. 2009;114(2 Pt 1):386-97.
- WHO Guidelines Approved by the Guidelines Review Committee. WHO Recommendations for Induction of Labour. Geneva: World Health Organization (c) World Health Organization 2011.; 2011.
- National Institute for Health and Care Excellence. CG70: Inducing labour. 2008.
- Leduc D, Biringer A, Lee L, Dy J. Induction of labour. Journal of obstetrics and gynaecology Canada : JOGC = Journal d'obstetrique et gynecologie du Canada : JOGC. 2013;35(9):840-57.
- Sharp AN, Stock SJ, Alfirevic Z. Outpatient induction of labour in the UK: a survey of practice. European journal of obstetrics, gynecology, and reproductive biology. 2016;204:21-3.
- Barnfield L, Neale E, Reynolds S. Outpatient cervical ripening in a district general hospital: a five-year retrospective cohort study. Journal of obstetrics and gynaecology : the journal of the Institute of Obstetrics and Gynaecology. 2018;38(3):301-4.
- Leopold B, Sciscione A. Is There a Place for Outpatient Preinduction Cervical Ripening? Obstetrics and gynecology clinics of North America. 2017;44(4):583-91.
- Sciscione AC, Muench M, Pollock M, Jenkins TM, Tildon-Burton J, Colmorgen GH. Transcervical Foley catheter for preinduction cervical ripening in an outpatient versus inpatient setting. Obstetrics and gynecology. 2001;98(5 Pt 1):751-6.
- Howard K, Gerard K, Adelson P, Bryce R, Wilkinson C, Turnbull D. Women's preferences for inpatient and outpatient priming for labour induction: a discrete choice experiment. BMC health services research. 2014;14:330.
- Alfirevic Z, Keeney E, Dowswell T, Welton NJ, Dias S, Jones LV, et al. Labour induction with prostaglandins: a systematic review and network meta-analysis. BMJ. 2015;350:h217.
- Vogel JP, Osoti AO, Kelly AJ, Livio S, Norman JE, Alfirevic Z. Pharmacological and mechanical interventions for labour induction in outpatient settings. The Cochrane database of systematic reviews. 2017;9:Cd007701.
- Kelly AJ, Alfirevic Z, Dowswell T. Outpatient versus inpatient induction of labour for improving birth outcomes. Cochrane Database of Systematic Reviews. 2009(2):CD007372.
- Dodd JM, Crowther CA. Misoprostol for induction of labour to terminate pregnancy in the second or third trimester for women with a fetal anomaly or after intrauterine fetal death. The Cochrane database of systematic reviews. 2010(4):Cd004901.