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General product information only, not medical advice. Clinical questions belong with a qualified clinician.
Short answer
A Pratt dilator is a rigid, fixed-size cervical dilator (a bougie) sold in double-ended sets and sized in French (Fr) units, with each instrument carrying two consecutive odd sizes such as 13/15 Fr. In the US, FDA classifies fixed-size cervical dilators as Class I devices under 21 CFR 884.4530. Hegar dilators are the same device family, but they are usually sized in millimetres.
Definition and scope
CooperSurgical, a manufacturer of the instrument, states that its Pratt cervical dilators are “designed to dilate the cervical canal” to allow entry into the uterus for evaluation of the cervical canal or uterine cavity (read 2026-11-07). That is a statement of intended use for the product, not guidance on how to use it.
Regulation 21 CFR 884.4530 groups obstetric-gynecologic specialized manual instruments and says structural integrity is the chief criterion of device performance. Among the devices it lists as Class I, exempt from premarket notification subject to 21 CFR 884.9, is the “cervical dilator (fixed-size bougies)”. The same group includes the uterine curette. openFDA lists the product code as HDQ, “Dilator, Cervical, Fixed Size”, Class 1, regulation number 884.4530 (queried 2026-11-07).
How it is described in practice
This page does not give procedural instructions. Procedure-level questions, including whether a dilator is moved in and out, depend on the clinical setting and the manufacturer’s instructions for use, and are decided by the treating clinician.
What the sources do say concerns the instrument format. CooperSurgical lists Pratt dilators as paired sizes: 13/15, 17/19, 21/23, 25/27, 29/31, 33/35, 37/39, 41/43, 45/47, 49/51, 53/55 and 57/59 Fr, plus an eight-piece set covering 13/15 through 41/43 Fr. The manufacturer page does not state the material or sterility status, so neither is asserted here; check the instructions for use supplied with a specific product.
Pratt vs Hegar and other cervical dilators
A vendor comparison (Gulmaher Surgico, “Hegar vs Pratt dilators”, read 2026-11-07) describes the two as differing in taper and sizing: Hegar with a long, gradual taper and millimetre markings, Pratt with a shorter, steeper taper and an odd-number French-gauge sequence (13, 15, 17, 19), which the vendor says means fewer size changes. This is a vendor description, not a regulatory or clinical standard.
The table below puts the FDA classification of related dilator product codes next to that, using openFDA (queried 2026-11-07).
| Device type (FDA product name) | Product code | Class | Regulation |
|---|---|---|---|
| Dilator, Cervical, Fixed Size (rigid bougies) | HDQ | 1 | 21 CFR 884.4530 |
| Dilator, Cervical, Hygroscopic-Laminaria | HDY | 2 | 21 CFR 884.4260 |
| Dilator, Cervical, Synthetic, Osmotic | PKN | 2 | 21 CFR 884.4260 |
| Dilator, Vaginal | HDX | 2 | 21 CFR 884.3900 |
The osmotic types are covered in Laminaria: Natural vs Synthetic Osmotic Dilators and FDA Class, and the balloon type in Cervical Ripening Balloon: What the IFU Says.
Where it matters for clinics and supply decisions
- Know the sizing scale on the label. Fr pairs (Pratt-style listings) and millimetre markings (Hegar-style listings, per the vendor above) are different scales, so a listing should be read for the unit it uses before it is compared with another.
- Class affects regulatory paperwork, not instructions. Class I fixed-size dilators are exempt from premarket notification subject to 21 CFR 884.9, while the osmotic types above are Class 2. The classification does not tell a user how to use any instrument.
- Follow the product’s own instructions for use for reprocessing, sterility and handling, since the category rules do not state these.
Common misunderstandings
- “Pratt” and “Hegar” are different device classes. Both are fixed-size cervical dilators; the difference the vendor describes is taper and sizing convention.
- Cervical and vaginal dilators are interchangeable. They are not. The openFDA product code HDX, “Dilator, Vaginal”, maps to 21 CFR 884.3900 (vaginal stent), a Class II device, separate from the Class I cervical dilator.
FAQ
What is the purpose of a cervical dilator?
According to CooperSurgical’s product page for Pratt dilators, it is to dilate the cervical canal so an instrument can enter the uterus for evaluation of the cervical canal or uterine cavity.
Should you move a dilator in and out?
This page does not give procedural direction. Handling of any dilator is a clinical matter set by the treating clinician and the manufacturer’s instructions for use. For a vaginal dilator, ask the clinician who recommended it.
Do pelvic floor therapists use dilators?
That is a question about vaginal dilators, a different device from the cervical Pratt dilator. FDA lists the vaginal dilator product code (HDX) under 21 CFR 884.3900 as Class II. Whether one is appropriate for a person is an individual clinical decision, so speak with a clinician.
What are the differences between a Hegar dilator and a Pratt dilator?
Per the vendor comparison above, Hegar dilators are described as having a long taper and millimetre sizing, and Pratt dilators a steeper taper and French-gauge pairs such as 13/15 Fr. FDA groups fixed-size cervical dilators under one product code (HDQ).
Sources
- 21 CFR 884.4530, Obstetric-gynecologic specialized manual instrument (Cornell LII, read 2026-11-07)
- 21 CFR 884.3900, Vaginal stent (Cornell LII, read 2026-11-07)
- openFDA device classification API, product codes HDQ, HDY, PKN, HDX (api.fda.gov, queried 2026-11-07)
- CooperSurgical, Pratt Cervical Dilators (manufacturer product page, read 2026-11-07)
- Gulmaher Surgico, Hegar vs Pratt dilators (vendor page, read 2026-11-07)
