What it is
The Cook catheter is a purpose-designed double-balloon device: one balloon sits above the cervix (inside the uterus) and one below (in the vagina), applying pressure from both sides. Like the Foley, it works mechanically without medication. Some studies suggest similar effectiveness to the single-balloon Foley; some show slightly faster ripening.
Evidence review links
Each link opens the full review on the publisher's site in a new tab.
Possible benefits
- Mechanical option without prostaglandin exposure (safer with prior cesarean)Review sources ↓
- Can be done as outpatient in some settingsReview sources ↓
- Comparable safety profile to FoleyReview sources ↓
Possible risks
- Discomfort with placement and while in placeReview sources ↓
- Rare risk of rupture of membranesReview sources ↓
- Cost/availability varies vs. FoleyReview sources ↓
Alternatives
- Foley bulb (single-balloon, most common mechanical option)Review sources ↓
- Prostaglandins (misoprostol, dinoprostone/Cervidil)Review sources ↓
- Membrane sweepReview sources ↓
- Awaiting spontaneous laborReview sources ↓
Current evidence
Meta-analyses (Salim et al. 2018; ACOG PB 107) show similar efficacy between single- and double-balloon devices, with the choice often driven by hospital preference.
Where the evidence is clear · where people may choose differently
For most topics, guidelines from ACOG, WHO, and other major bodies broadly agree on the core safety points (when to act in an emergency, informed-consent standards, monitoring baselines). Where reasonable people — and even guidelines — differ tends to be around thresholds (when to start or stop something), preferences (comfort, environment, support), and values (how you weigh small risks against benefits). Use the questions below to explore those pieces with your care team.
Educational only. Your care team can help you weigh what applies to your specific situation.
Related evidence topics
- Induction: Foley / Cook Balloon (Mechanical Ripening)A small balloon catheter placed in the cervix and filled with saline to help it dilate — a medication-free ripening method.
- Induction of LaborMedical methods used to start labor before it begins on its own — see the method-specific topics below for details.
- Bishop Score — How "Ready" the Cervix IsA 0–13 point score your provider uses before an induction to predict how likely it is to end in a vaginal birth.
- Induction: Misoprostol (Cytotec)A prostaglandin tablet given by mouth or vaginally to ripen the cervix and often start contractions.
Questions to ask your care team
- ?Which mechanical option does this hospital use, and why?
- ?Can it be done outpatient, and when do I come back?
- ?What's the plan if it falls out or if my water breaks?
Universal questions (works for any decision)
A short BRAIN-style set you can bring to any conversation about interventions, monitoring, or care decisions.
- ?Why are you recommending this now — is it urgent, routine, or optional?
- ?What happens if we wait an hour (or longer) before deciding?
- ?What signs would tell us this is working — or that we need to change course?
- ?What are the alternatives, including doing nothing?
- ?What would you recommend if this were your family?
- ?What would change your recommendation?
Sources & provenance
Tap a source to open the original guideline or review in a new tab.
- ACOG Practice Bulletin 107: Induction of Labor — ACOG
- Salim et al. — Single-balloon compared with double-balloon catheters for induction of labor — Obstetrics & Gynecology
Plain-language paraphrase. Re-verify before publish.
Last reviewed: 2026-07-03
Further reading — canonical references
Read the source material directly. Each link opens the publisher's own current guidance in a new tab — cross-check what we summarize against what they say.
Tier 1 · Clinical guidelines
- ACOG guidance on “Cook (Double-Balloon) Catheter for Cervical Ripening”ACOG — U.S. clinical guidelines from the American College of Obstetricians and Gynecologists.
- NICE guidance on “Cook (Double-Balloon) Catheter for Cervical Ripening”NICE — UK clinical guidelines — often useful when ACOG and WHO differ.
Tier 2 · Systematic reviews
- Cochrane reviews on “Cook (Double-Balloon) Catheter for Cervical Ripening”Cochrane Library — Systematic reviews — top of the evidence stack when available.
- PubMed studies on “Cook (Double-Balloon) Catheter for Cervical Ripening”PubMed — Primary research — filter by review or meta-analysis for strongest evidence.
Educational only. Guidelines evolve — the linked publisher pages will reflect newer guidance than any static snapshot.
Version history — v1.0.0
v1.0.0 · 2026-07-03 · LlaMamma editors
Initial Cook balloon topic.
New guidance from ACOG, WHO, Evidence Based Birth, or other listed sources is recorded here and can be updated remotely without a new app release.