Inpatient Versus Outpatient Cervical Ripening

Induction of labor is a process of stimulating uterine contractions before the onset of labor, with a goal of achieving vaginal birth. The cervix (the lower part of the uterus that connects to the vagina) must dilate (open) in order to allow passage of the baby into the vagina and through the birth canal. A process called "cervical ripening" is often performed prior to labor induction to prepare the cervix for labor and therefore shorten the length of the labor. There are various pharmacologic and mechanical methods of cervical ripening that result in the physical softening and distensibility of the cervix. Mechanical dilation with a small balloon (i.e. a Foley catheter) placed in the cervix is one of the most commonly used, safe, inexpensive, and effective methods to achieve cervical ripening.

In most hospitals, cervical ripening is performed in the hospitals; however, some hospitals allow women to undergo cervical ripening at home with a transcervical Foley catheter. The goal of this study is to compare the use of a Foley catheter for cervical ripening in the inpatient (in-hospital) and outpatient (at home) settings. We anticipate that outpatient use will lead to a shorter amount of time that a woman spends in the hospital, decreased cost, and good patient satisfaction.

From 1990 to 2010, the rates of induction of labor increased from 9.6% to 23.8%(1). Recent data from 2014 reports a rate of 23.2%(2). Labor induction may be medically indicated, in cases in which the risk of continuing pregnancy is greater than delivery, or in some cases electively after 39 weeks of gestation.

Prior to starting an induction of labor, a digital exam is performed to determine the status of the cervix in terms of its dilatation, effacement, position, softness, and fetal station. If the cervical status is considered favorable for labor, then generally oxytocin is started to induce uterine contractions. If the cervix is not considered favorable, a method of cervical ripening is employed to induce physical changes in the cervix that make it more favorable for labor.

This process involves inflammatory infiltration and release of metalloproteases that degrade collagen and result in cervical remodeling(3). The primary benefit of cervical ripening is reducing the length of labor; however, some studies have suggested that it may lower the rate of cesarean section(4,5). The Bishop score (see table 1) is used as a scoring tool to determine the status of the cervix(6). Most studies define a score of 6 or less as an unfavorable cervix, while a score of greater than 8 is favorable, and has a similar probability of vaginal delivery to spontaneous labor(7).

Commonly used methods for cervical ripening include pharmacologic forms such as synthetic prostaglandin E1 (PGE1, i.e. misoprostol) and prostaglandin E2 (PGE2, i.e. dinoprostone), or mechanical ripening with balloon (i.e. Foley) catheters.

Quality improvement, increasing efficiency, and decreasing cost continue to be challenges for individual hospitals and the entire health care system. Induction of labor, especially with an unfavorable cervix, is associated with longer lengths of stay for patients, which results in increased cost(8).

Foley catheters are a safe, inexpensive and effective option for cervical ripening. A study by Sciscione et al in 2001 compared Foley bulb use in inpatient versus outpatient settings and found the outpatient use to be as effective for cervical ripening. The primary objective of this study was to compare efficacy of these two approaches and the outcomes were similar. There were no cases of endomyometritis or chorioamnionitis(9). While they did report a shorter amount of time in the hospital with outpatient management, this was not a primary outcome of the study and they did not compare costs. Recently there has been an increased focus on the costs of medical care and patient satisfaction. Consequently, these are increasingly important outcomes that research needs to focus on. It is our hope that the findings of our study will support the use of outpatient pre-induction of labor cervical ripening and result in a more efficient use of resources and improved patient satisfaction.

The purpose of this study is to compare the use of a Foley catheter for cervical ripening in the inpatient and outpatient setting, in order to evaluate the difference in the amount of time spent on labor and delivery during induction of labor, as well as the difference in costs. An important secondary outcome we plan to evaluate as well is patient satisfaction. This will be a randomized controlled trial, with the study population being pregnant women at ≥ 37 weeks of gestation undergoing induction of labor. The projected time-frame will be from October 2016 to June 2018. The expected outcome is that outpatient cervical ripening with Foley catheter use will result in shorter lengths of stay on labor and delivery and less cost than inpatient Foley catheter use in patients undergoing induction of labor. Additionally, we anticipate greater patient satisfaction with outpatient management.

Eligibility Criteria:
Inclusion Criteria:

* Pregnancies at least 37 weeks' gestation, undergoing induction of labor, with an unfavorable cervix, defined as a Bishop score ≤ 6
* The fetus must be in the cephalic presentation
* Indications for induction of labor include, but are not limited to, the following:

  * Elective induction of labor at 39 weeks' gestation
  * Intrauterine growth restriction
  * Chronic hypertension
  * Diabetes
  * Gestational diabetes
  * Prior stillbirth
  * Other medical indications for induction of labor, as deemed appropriate by the obstetric provider, such as Systemic Lupus Erythematosus, Cholestasis of Pregnancy etc.

Exclusion Criteria:

* Gestational hypertension
* Preeclampsia
* Non-reassuring fetal testing
* Multi-fetal gestation
* Oligohydramnios
* Fetal anomaly
* Less than 37 weeks
* Bishop score \> 6
* Ruptured membranes
* Contraindication to vaginal delivery including: active Herpes lesion, HIV VL \>1000 copies/mL, placenta previa, vasa previa, breech presentation, prior classical cesarean section or transfundal myomectomy
* Poor access to telephone or transportation
* Latex allergy
* Any other condition for which the managing physician or investigator deem outpatient management inappropriate.
* Currently participating in another clinical trial