Elsevier

Seminars in Perinatology

Volume 39, Issue 6, October 2015, Pages 441-443
Seminars in Perinatology

Intracervical Foley balloon catheter for cervical ripening and labor induction: A review

https://doi.org/10.1053/j.semperi.2015.07.005Get rights and content

Abstract

Labor induction is a common obstetric practice. Optimal methods of both ripening and induction are debated. This article assesses the intracervical Foley balloon catheter through review of literature, including meta-analyses, randomized controlled trials, and retrospective data. Discussion includes comparison of Foley balloon catheters to pharmacologic agents, safety profile in various clinical scenarios, and cost-effectiveness.

Introduction

Approximately 20% of laboring women undergo induction for maternal or fetal indications.1 Labor can be induced by mechanical methods, such as intracervical Foley balloon catheters, hygroscopic dilators such as Laminaria and Dilapan, and amniotomy. It can also be accomplished with the use of exogenously administered prostaglandins, such as misoprostol and dinoprostone. All of these options ripen the cervix, thus softening the cervix and preparing it for labor.

Mechanical methods of cervical ripening and labor induction are safe and effective. One of the most effective induction tools is the Foley balloon catheter. To understand how the Foley balloon catheter incites cervical change, one must understand the structure of the cervix and how labor begins and progresses.

Remodeling of the cervix occurs in 4 phases: softening, ripening, dilation, and repair after delivery. Softening occurs throughout gestation. Ripening is defined as the peak of cervical tissue loss of tensile strength and structure. Dilation proceeds once the cervix is ripe and causes both the external and internal cervical os to open.2, 3

The cervix contains extracellular fibrous tissue matrices composed of types 1 and 3 collagen, glycosaminoglycans, and matrix proteins. During parturition, these matrices are degraded and remodeled. The tissue tensile strength decreases because of degradation of collagen cross-links. As labor progresses, endogenous prostaglandins are released that stimulate stretch forces on myometrial cells and the overlying amnion. E-cadherin is up-regulated by cervical epithelial cells, which further increases tissue breakdown. Progesterone synthesis declines, while estradiol concentrations increase. This increases the concentration of aquaporins and gap junctions. Cervical water content subsequently increases, which further remodels the cervical extracellular matrices.4 As prostaglandins circulate, local inflammatory responses cause alterations in tissue gene expression. All of these mechanisms help to soften, efface, and subsequently dilate the cervix.2

Section snippets

Purpose

Cervical ripening is often required to make the cervix more favorable for induction. In women with low Bishop scores (a score less than 6 is called an unfavorable cervix and likely requires ripening), a favorable option is to ripen the cervix with a Foley bulb transcervical catheter. The Foley bulb softens and stretches the cervix mechanically and stimulates endogenous prostaglandin release.5

Methods

Typically, a standard 16-F latex or latex-free Foley catheter is used. There is also a specialized Cook catheter, which small studies have shown to be less efficacious and more costly.6 The Foley bulb is placed into the internal cervical os. This can be accomplished digitally or visually with a speculum and ring forceps. The balloon is filled with 30−60 ml of sterile water. The Foley catheter is taped to tension on the patient’s medial thigh in order to exert pressure on the internal cervical

Research

Foley catheter balloons are often preferred to pharmacologic agents. There is less uterine hyperstimulation and tachysystole with mechanical methods.8, 9, 10 The PROBAAT trial, a randomized controlled trial of 824 women, compared Foley catheters to dinoprostone gel for cervical ripening.11 Outcomes were measured by cesarean section rate, maternal and neonatal morbidity, and time from intervention to birth. The rate of cesarean section was essentially the same [93 (23%) Foley bulb versus 82

Prior cesarean section

Controversy surrounds use of Foley catheter balloons in women desiring trial of labor after cesarean section. Bujold et al. studied women with a prior low transverse cesarean section. Their results showed no significant difference in uterine rupture rates between women induced with a Foley catheter balloon versus women who entered labor spontaneously.17 However, in a retrospective analysis of 972 women attempting trial of labor after a prior low transverse cesarean section, Hoffman et al.18

Ruptured membranes

It is unclear whether Foley balloon catheters decrease time from induction to delivery and cesarean section rates in women with premature rupture of membranes and preterm premature rupture of membranes without labor. Retrospective data of women induced by Foley balloon catheter and misoprostol showed that Foley balloon catheters may shorten time to delivery.19 Since Foley balloon catheters are foreign objects, they predispose women to intrauterine infection. However, the risk of

Conclusion

Intracervical Foley balloon catheters are a relatively safe and effective way to ripen the cervix compared to other cervical ripening agents. Due to their low cost and lower rates of uterine hyperstimulation, they are an excellent tool to use both in prospering and developing countries. Numerous studies show that Foley balloon catheters are equivalent to pharmacologic methods with rates of failed induction of labor and cesarean section. However, their safety profile makes them an attractive

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Dr. Victoria Greenberg is a resident physician at Christiana Care Health Services.

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