Rain This Morning, Unfavorable Cervical Conditions This Afternoon

A product called a cervical ripening balloon (intended for labor induction) was introduced by Cook Medical and a recent meeting of the American College of Obstetricians and Gynecologists –

The Cook Cervical Ripening Balloon offers a safe, simple method for cervical ripening in unfavorable cervical conditions…

The idea is something like any other balloon catheter (such as those used in angioplasty) to open up a part of the body. In this case, there are two balloons, one that sits just inside the cervical opening, and one that sits just outside of it, and these are inflated with saline to help dilate the cervix. Think of it as stretching a rubber band by putting it around a balloon and blowing up the balloon.

Interestingly, given the current climate of let’s-do-a-c-section-just-to-be-safe, Cook is using the language of vaginal birth promotion in its press release on the product, and framing it in terms of safety and a better birth experience:

“Studies have shown in the past few years that in the absence of a favorable or ripe cervix, a successful vaginal birth is less likely,” says Christina Anné, global leader of Cook Women’s Health. “Not only does the Cook Cervical Ripening Balloon improve the success rate of labor induction by safely ripening and dilating the cervix and eliminating the side effects of common medications and mechanical methods used to induce labor, it can also provide women with an easier, more comfortable birthing experience.

 

If labor is induced when the cervix is unfavorable it may increase the likelihood of induction failure, protracted and exhausting labors, and other complications. An undesired Cesarean delivery may also result.”

Cook provides three citations on the use of the device:
Atad J, Hallak M, Ben-David Y, Auslender R, Abramovici H. Ripening and dilation of the unfavorable cervix for induction of labor by a double balloon device: experience with 250 cases. Br J Obstet Gynaecol. 1997;104 (pt 1): 29.
I don’t have this electronically, but the abstract indicates that the device was tried win women with Bishop scores of 4 or less (meaning that labor was considered unlikely to start without induction) and had pregnancy-induced hypertension, were post-date, were having elective inductions, or other reasons for induction such as previous c-section or diabetes. The device stayed in place for 12 hours before it was removed, and women on average delivered 6.9 hours after it was removed. Only 16% of patients ended up having a c-section, and mean Bishop score increased from 2.2 to 6.6.

Atad J, Hallak M, Auslender R, Porat-Packer T, Zarfati D, Abramovici H. A randomized comparison of prostaglandin E2, oxytocin and the double-balloon device in inducing labor. Obstet Gynecol. 1996; 87:223-227.
I do have access to this article. Note, however, that it includes a disclosure that the author (Atad, same as for the paper above) has a financial stake in the sale of the product. Women were enrolled for similar reasons as above, and the cervical device was used in one group of women to be compared to women receiving standard induction drugs, oxytocin or prostaglandin E2. It was a relatively small study, with ~30 women in each group. The authors report that the success rate for vaginal delivery is reported as significantly higher in the device group, and outcomes for the newborns were similar across groups. See the paper for additional details, or email me if you have questions about the other results (Bishop scores, etc.).

Sherman D, Frenkel E, Tovbin J, Arieli S, Caspi E, Bukovsky I. Ripening of the unfavorable cervix with extra-amniotic catheter balloon: clinical experience and review. Obstet Gynecol Survey. 1996; 51 (10): 621-627.
This is basically a review article (describing other papers) with description of a small study group added on. As a result, it is somewhat hard to follow and rather less useful than the other papers. However, the authors suggest that this balloon method is simple, safe, and low cost in a majority of cases, but note that additional labor stimulation with oxytocin may be needed in a good number of cases.

Although Foley catheters and single balloon devices have been previously studied for this purpose, there are only a handful on the double balloon device from Cook, and about half are authored by Atad. Additionally, the device does not appear to be listed in the FDA’s database of approved medical devices (although the FDA site overall is notoriously difficult to search).

What does it all mean? Those who advocate less medicalized birth, such as Marsden Wagner, have suggested that too-high rates of labor induction via drugs is partially responsible for the too-high rate of c-section in this country. Perhaps this cervical ripening balloon device can, if safe, help improve birth for women by causing a move away from drug-based inductions. I’d be interested in seeing larger studies of the device with more patients and by other authors.

[Hat tip to Medgadget]