Original Article


The Timing of Adverse Events with Foley Catheter Preinduction Cervical Ripening; Implications for Outpatient Use

1 Department of Obstetrics and Gynecology, Christiana Hospital,

Newark, Delaware Am J Perinatol 2014;31:781–786.



► ► ► ►

preinduction Foley catheter safety cervical ripening

Matthew K. Hoffman, MD, MPH1

Address for correspondence Anthony C. Sciscione, DO, Department of Obstetrics and Gynecology, Christiana Care Health Services, 4755 Ogletown-Stanton Road, Newark, DE 19718 (e-mail: [email protected]).

Objective We sought to determine the rate and timing of adverse events that occur during preinduction cervical ripening using the Foley catheter before extrusion of the balloon and institution of oxytocin. Study Design Using electronic medical records, we identified all women who presented for preinduction cervical ripening using a Foley catheter with a term (37 weeks) singleton vertex live fetus from January 1, 2006, to June 14, 2009. Women were excluded if they had had a previous cesarean delivery, gestational hypertension or preeclampsia, pregestational diabetes, rupture of membranes before induction, fetal anomaly, or antepartum stillbirth. Outcomes were cesarean delivery for nonreassuring fetal tracing, vaginal bleeding, placental abruption, or intrapartum stillbirth occurring between 2 hours after Foley catheter placement and 6 AM. Results Among 2,514 women, 1,905 met the inclusion criteria. No adverse outcomes were noted among term, singleton uncomplicated pregnancies receiving a Foley catheter for preinduction cervical ripening who met inclusion criteria (relative risk, 0.0; 95% confidence interval, 0.0–0.002). Conclusions In a low-risk population, the use of the Foley catheter for preinduction cervical ripening was associated with no adverse outcomes. It appears to be a safe mechanism for cervical ripening and has the potential for use in the outpatient setting in a selected subset of women.

Induction of labor has become one of the most frequently performed obstetrical procedures in the United States. According to the National Center for Health Statistics, the overall rate of labor induction in 2006 was 22.6%, more than twofold increase from the previous year.1 Induction of labor is often preceded by preinduction cervical ripening which can be performed by mechanical or pharmacologic methods and is often a protracted process. Although the ideal method of cervical ripening remains unclear, the optimal method is one that is safe, cost-effective, and does not require inpatient monitoring; potentially lowering costs.2

The Foley catheter is an effective method for preinduction cervical ripening when compared with pharmacologic methods.2,3 The Foley catheter is equally effective for cervical ripening in the outpatient as the inpatient setting in terms of mean change in Bishop score, maximum dose of oxytocin, induction time, and 1- and 5-minute Apgar scores. Moreover, outpatient management resulted in 9.6 less hours of hospitalization and few revisits to the hospital during that time period.4 Likewise, studies have demonstrated higher rates of satisfaction among women randomized to outpatient management with several methods of cervical ripening.5 Although these reports

received June 21, 2013 accepted after revision September 30, 2013 published online December 17, 2013

Copyright © 2014 by Thieme Medical Publishers, Inc., 333 Seventh Avenue, New York, NY 10001, USA. Tel: +1(212) 584-4662.

DOI http://dx.doi.org/ 10.1055/s-0033-1359718. ISSN 0735-1631.

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Anthony C. Sciscione, DO1 Casey L. Bedder, DO1 Kelly Ruhstaller, MD1 Phillip A. Shlossman, MD1

The Foley Catheter; Implications for Outpatient Use

Sciscione et al.

have found that outpatient preinduction cervical ripening with the Foley catheter is both effective and more acceptable to women, they have not adequately addressed the question of safety nor clearly identified appropriate women for outpatient management. We sought to determine the risk of selected adverse pregnancy outcomes in a low-risk population of women who underwent preinduction cervical ripening with the Foley catheter in the hospital setting.

Materials and Methods After the approval from the institutional review board at the Christiana Care Health System, a retrospective cohort of all induction of labors that received preinduction cervical ripening with the Foley bulb from January 1, 2006, to June 14, 2009, were identified from a contemporaneously maintained obstetrical database. This database is obtained through nursing electronic documentation as part of routine clinical care. The database is validated daily for completeness and quarterly for accuracy. Repeated audits of key variables have shown accuracy greater than 95%.6 Where data were unavailable, chart abstraction was performed by a single investigator (CLB). Women were included in the study if they presented with a singleton, live, vertex fetus at greater than or equal to 37 weeks gestation for preinduction cervical ripening. The Foley catheter and no other agent could be used either sequentially or concomitantly for cervical ripening. Exclusion criteria included multiple gestations, previous cesarean delivery, known contraindications to vaginal delivery, gestational hypertension or preeclampsia, pregestational diabetes, or rupture of membranes before induction or during Foley catheter placement. To assess the potential for an adverse outcome using an outpatient protocol, women who had an

Fig. 1 Study flow diagram.

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adverse obstetric event in the 2 hours following placement or after 6 AM were not included in the analysis since they would have been managed in the inpatient setting. A standard method for placing the Foley catheter was employed. Each woman had a 16 Foley catheter inserted through the endocervical canal, advanced to or just past the internal os and filled with 30 mL of sterile water; use of a speculum for placement was provider dependent.4,7,8 The vagina and cervix was not cleaned before insertion. The catheter is then placed on gentle traction by taping the end of the catheter to the medial thigh. Typically, the catheter was placed in the late afternoon or early evening based on patient convenience. The outcomes of our study were nonreassuring fetal tracing necessitating cesarean delivery, abruption, or intrapartum stillbirth during the time period starting 2 hours postcatheter insertion until 6 AM. This time period was chosen in an effort to reproduce the time when a woman would be managed in an outpatient setting. In the previously described outpatient trial, women were monitored for 2 hours after placement of the Foley catheter (usually 9–11 PM), sent home if their nonstress testing was reactive and asked to return to labor and delivery at 6 in the morning to continue their induction of labor.4 Data analysis consisted of univariable statistical analysis using Stata 10.0 (College Station, TX). The rate of the primary outcome was calculated by performing binomial confidence intervals.

Results A total of 2,514 women underwent preinduction cervical ripening with the Foley catheter in the study period. Of these women, 1,905 met criteria for analysis (►Fig. 1). Our most common exclusion was gestational age of < 37 weeks

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The Foley Catheter; Implications for Outpatient Use

Table 1 Maternal and fetal demographics Maternal demographics Age, y


SD  6.1



Range (1–11)



Range (0–10)

Ethnicity White


African American






Mixed race


Provider type Private






Fetal demographics 39.6

SD  1.2

Birthweight (g)


SD  501

NICU admission


Gestational weeks

Abbreviations: NICU, neonatal intensive care unit; SD, standard deviation.


Table 2 Indications for induction N


% of total

Postdates (41 wk)






Gestational diabetes mellitus



Chronic hypertension



Growth restriction or other fetal indication









occurred in the process of labor (0.05%) and four had 5 minute Apgar scores of 4 or less (0.73%); these events occurred outside of our study time frame. In reviewing their fetal heart rate tracings, all four had category I tracings at 6 AM. None of these outcomes in the induction of labor period are likely related to the use of the Foley catheter during the preinduction cervical ripening period. ►Table 3 contains labor outcome information.

Discussion The process that initiates labor is still unclear; it is apparent that cervical ripening likely occurs over multiple weeks before the initiation of labor through a complex interplay of both mechanical and pharmacologic processes. Naturally, the approach to the induction of labor has evolved into a similar process with the induction of labor often proceeded by preinduction cervical ripening. The cervical ripening process is often the longest part of the procedure and can be achieved by mechanical and pharmacologic methods. Although there are several methods for mechanical ripening, the Foley catheter is the most commonly used method. When compared with pharmacologic methods, it has similar cesarean delivery rates, failed induction rates, and induction to delivery intervals with a significant decrease in contractile abnormalities and meconium passage when compared with some pharmacologic methods.3,8,9 The primary mechanism of action of the Foley catheter is mechanical and the rate of side effects appears low with the most common being mild discomfort with placement. As such, the Foley catheter is likely an ideal mechanism for outpatient cervical ripening. A report that examined its use in the outpatient setting reported that no patient who was randomized to the outpatient arm withdrew from the trial, crossed over to the inpatient arm, or returned to the hospital for pain and that the device was as efficacious in the outpatient setting as when used inpatient.4 Although the previous report showed that the Foley was well tolerated and effective in the outpatient setting, there have been no large reports examining adverse outcomes. We felt that before transitioning the Foley catheter to an outpatient setting or even to an unmonitored setting, the safety of the device had to be examined. Although no report has found adverse events associated with the Foley American Journal of Perinatology

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(N ¼ 239). Maternal demographic and fetal demographics are presented in ►Table 1. The majority of our women were white (62.9%) and nulliparous. Reasons for induction of labor are summarized in ►Table 2. The most common reason for induction was postdates defined as a gestational age  41 weeks. Elective induction was common in this population (25%), though the introduction of departmental guidelines now preclude this. Five women had a cesarean delivery between placement of the Foley catheter and 6 AM (►Fig. 2). Two women underwent a cesarean delivery during the period after Foley catheter placement but before completing the 2 hours of monitoring. The indication for both deliveries was nonreassuring fetal heart tracings. There were three cesarean deliveries during the time frame of our study, 2 hours after placement until 6 AM; one for face presentation and two for arrest of dilatation. All three of these women went into spontaneous labor and/or had rupture of membranes during the 2-hour observation and monitoring period. None of these three cesareans had nonreassuring fetal tracings; one infant had Apgar scores of seven and nine at 1 and 5 minutes, and the other two infants both had Apgar scores of eight and nine at 1 and 5 minutes. There were no cesarean deliveries performed for nonreassuring fetal heart tracing or abruption nor any cases of intrapartum stillbirth that occurred during the study time period (relative risk, 0.0; 95% confidence interval, 0.0–0.002). Although no adverse events occurred during our study interval, there were instances of the previously defined adverse events (abruption, cesarean delivery for nonreassuring fetal testing) during the entire labor course of our cohort (►Fig. 2). One woman had an abruption that

Sciscione et al.

The Foley Catheter; Implications for Outpatient Use

Sciscione et al.

Fig. 2 Patient flow diagram.

catheter for preinduction cervical ripening, there has never been a large comprehension review. Our analysis showed that in a low-risk population, during the preinduction cervical ripening period, the Foley catheter was associated with no adverse obstetric events. We chose our specific time frame, 2 hours after monitoring until 6 AM based on the previously reported outpatient management trial and as a guide for future outpatient protocols.4 There were five cesarean deliveries in our study cohort from the time of placement of the Foley catheter until 6 AM. However, based on our proposed protocol (►Table 4), these women would not have been discharged to home; they would have been excluded from outpatient management during the 2-hour monitoring period due to rupture of membranes, nonreassuring fetal heart tracing, or onset of spontaneous labor. Another key for transitioning the process of cervical ripening out of the hospital will be patient selection. The women we included in our calculations were low risk from an obstetrical perspective (►Fig. 1). We excluded any patients being induced before 37 weeks of gestation with a mean gestational age of 39.6 weeks. Any patients with medical conditions that might require intervention during the induc-

Table 3 Overall labor outcomes for the entire labor Variable

Percentage, %

Method of delivery Vaginal


Cesarean for arrest


Cesarean for NRFHR


Cesarean other


Other variables Epidural rate

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tion process such as pregestational diabetics or women with gestational hypertension or preeclampsia were not included. Women with a prior cesarean delivery were also excluded, although Foley catheter has not been associated with increased rates of uterine rupture in women attempting a trial of labor after cesarean delivery.10 In addition, the Foley

Table 4 Proposed outpatient protocol 1. Patient presents to OB triage at 8:00–9:00


2. Foley catheter placed by provider (attending, resident, nurse practitioner, midwife, physician’s assistant) • Confirm fetal presentation: vertex • Cervical exam < 3 cm dilated • 16-French Foley inserted through internal cervical os and inflated with 30 mL sterile water • Distal end of catheter placed on tension and taped to medial thigh 3. Two hours of monitoring and antenatal testing • Amniotic fluid volume assessed • Continuous electronic fetal monitoring 4. Patient discharged to home if: • AFI > 5 cm • Reactive NST with category I FHR  2 h • No vaginal bleeding, rupture of membranes, spontaneous labor • Maternal vital signs are within normal limits 5. Patient returns to hospital: • For rupture of membranes • For vaginal bleeding • For consistent contractions every 5–10 min • For decreased fetal movement • For severe pain • If fever greater than 100.5°F or 38°C develops • Once the Foley catheter comes out • At 5:00 AM to begin oxytocin at 6 AM Abbreviations: AFI, amniotic fluid index; FHR, fetal heart rate; NST, nonstress test.

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The Foley Catheter; Implications for Outpatient Use

Summary Preinduction cervical ripening with the Foley catheter is not associated with adverse events in appropriately selected women. Offering outpatient cervical ripening using the Foley catheter in this low-risk population appears reasonable.


Financial Disclosure This project was completed without the benefit of external funding. The authors are unaware of any potential commercial influences that would have affected the outcomes of this study. Reprints are not available.

References 1 Martin JA, Hamilton BE, Sutton PD, et al. Births: final data for 2006.

Natl Vital Stat Rep 2009;57(7):1–102 2 Gelber S, Sciscione A. Mechanical methods of cervical ripening and

labor induction. Clin Obstet Gynecol 2006;49(3):642–657 3 Vaknin Z, Kurzweil Y, Sherman D. Foley catheter balloon vs locally






9 10





applied prostaglandins for cervical ripening and labor induction: a systematic review and metaanalysis. Am J Obstet Gynecol 2010; 203(5):418–429 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. Obstet Gynecol 2001;98(5, Pt 1):751–756 Dowswell T, Kelly AJ, Livio S, Norman JE, Alfirevic Z. Different methods for the induction of labour in outpatient settings. Cochrane Database Syst Rev 2010;(8):CD007701 Zhang J, Troendle J, Reddy UM, et al; Consortium on Safe Labor. Contemporary cesarean delivery practice in the United States. Am J Obstet Gynecol 2010;203(4):e1, e10 Sciscione AC, McCullough H, Manley JS, Shlossman PA, Pollock M, Colmorgen GH. A prospective, randomized comparison of Foley catheter insertion versus intracervical prostaglandin E2 gel for preinduction cervical ripening. Am J Obstet Gynecol 1999;180(1, Pt 1):55–60 Sciscione AC, Nguyen L, Manley J, Pollock M, Maas B, Colmorgen G. A randomized comparison of transcervical Foley catheter to intravaginal misoprostol for preinduction cervical ripening. Obstet Gynecol 2001;97(4):603–607 Boulvain M, Kelly A, Lohse C, Stan C, Irion O. Mechanical methods for induction of labour. Cochrane Database Syst Rev 2001;(4):CD001233 Bujold E, Blackwell SC, Gauthier RJ. Cervical ripening with transcervical foley catheter and the risk of uterine rupture. Obstet Gynecol 2004;103(1):18–23 Hamilton BE, Martin JA, Ventura SJ. Births: preliminary data for 2007. National Vital Statistics Reports; Vol 57, no 12. Hyattsville, MD: National Center for Health Statistics; 2009 Seyb ST, Berka RJ, Socol ML, Dooley SL. Risk of cesarean delivery with elective induction of labor at term in nulliparous women. Obstet Gynecol 1999;94(4):600–607 Farmer KC, Schwartz WJ III, Rayburn WF, Turnbull G. A costminimization analysis of intracervical prostaglandin E2 for cervical ripening in an outpatient versus inpatient setting. Clin Ther 1996;18(4):747–756, discussion 702 Meyer M, Pflum J, Howard D. Outpatient misoprostol compared with dinoprostone gel for preinduction cervical ripening: a randomized controlled trial. Obstet Gynecol 2005;105(3):466–472

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catheter has been shown to have a high rate of patient compliance, patient satisfaction, and comparable clinical outcomes.5 In our institution, the Foley catheter is the main method for cervical ripening and the majority are placed by interns, midwives, or physician assistants. The device is well tolerated with rare instances where it cannot be inserted. Women do not receive pain medication before placement of the device nor require it after. The outpatient Foley catheter trial showed that the majority of women were able to manage the device at home with only 8% returning to the hospital before the specified time and most reporting that the experience was more favorable at home.4 The effectiveness of the Foley catheter versus alternative mechanisms of cervical ripening has been well established as a comparable device.2,3 In addition, its use in an outpatient setting has previously been determined to be as good as when used inpatient.4 Our institution’s rate of primary cesarean delivery is approximately 33.4%, consistent with the national average of 32%.11 The cesarean delivery rate in our cohort was elevated at 38.5%; however, this was likely due to the 25% rate of elective inductions and not a reflection of the use of the Foley catheter.12 It is important to recognize that while our dataset was large and diverse, including almost 2,000 patients, rare adverse outcomes cannot be accounted for. The results of our study are contingent on careful patient selection and establishing that the fetal status is reassuring as specified in our selection criteria and time frame. This report provides the evidence that in a low-risk population using the procedure described above is safe and can be considered for use in the outpatient setting. A woman who undergoes outpatient cervical ripening with a Foley catheter spends 9.6 hours less in the hospital.4 Women who are allowed to go through the early part of labor in a familiar setting, often at home, report a more favorable experience than those who labor in a hospital.4,13,14 Finally, the ability to move the cervical ripening process from an inpatient procedure to outpatient has the potential to reduce the utilization of health care resources.

Sciscione et al.

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The timing of adverse events with Foley catheter preinduction cervical ripening; implications for outpatient use.

We sought to determine the rate and timing of adverse events that occur during preinduction cervical ripening using the Foley catheter before extrusio...
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