Ring Pessary Size Guide — Sizes 0–9 (44–102 mm) Explained
Ring pessary size guide: sizes 0–9 (44–102 mm) explained.
A practical reference for patients and clinicians on ring pessary sizing. Standardized US ring pessary sizes, the most commonly fitted ranges, and how to work with your gynecologist to find the right size. Clinical claims on this page are referenced to peer-reviewed urogynecology literature (PMC, IUGA, POGP, FDA eCFR, Brigham & Women's, CU Anschutz).
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Ring pessaries are sized by outer diameter. US clinical convention uses size numbers 0 through 9, with each step roughly 6–7 mm larger than the last. Ring-shaped pessaries are the most commonly used pessary type and, per Cooley & Jones in Canadian Family Physician (PMC1949074), can treat approximately 80% of grade 1 and 2 prolapse cases. The chart below shows the full SciMed range.
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| Size | Diameter (mm) | Diameter (in) | Typical use |
|---|---|---|---|
| 0 | 44 mm | 1.75 in | Very small introitus |
| 1 | 51 mm | 2.00 in | Small introitus |
| 2 | 57 mm | 2.25 in | Smaller-than-average |
| 3 | 64 mm | 2.50 in | Common starting size |
| 4 | 70 mm | 2.75 in | Most commonly fitted |
| 5 | 76 mm | 3.00 in | Most commonly fitted |
| 6 | 83 mm | 3.25 in | Larger-than-average |
| 7 | 89 mm | 3.50 in | Larger introitus |
| 8 | 95 mm | 3.75 in | Post-vaginal-delivery, larger |
| 9 | 102 mm | 4.00 in | Largest available |
Highlighted rows (sizes 3–5) are the most commonly fitted sizes in US gynecology practice for first-time pessary users. The IUGA expert opinion on vaginal pessaries reports the ring pessary fits approximately 70% of women across the full clinical range.
How clinical fitting works
Pessary fitting is a brief in-office procedure performed by a gynecologist or urogynecologist. The University of Colorado Anschutz urogynecology team describes the process as inherently trial-and-error — "much like trying on shoes" — with most patients fitted within 1–2 attempts. The four-step process below is what most US providers follow; for additional clinical reference see the POGP UK Pessary Types Guide (April 2021) and Brigham & Women's Hospital pessary instructions.
Pelvic exam
Your provider examines for prolapse stage, vaginal length, and introital width.
Fitting trial
A fitting kit is used to trial sizes — typically starting around size 3 or 4.
Walk & valsalva
You walk, cough, and bear down to confirm the pessary stays in place comfortably.
Confirm size
Once a comfortable, retentive fit is confirmed, you order that size for daily use.
When to size up or down
Pessary fit can change over time — with weight change, after pelvic floor physical therapy, or following pelvic surgery. Here's how to recognize when a different size may help.
↑Consider sizing up if…
- The pessary falls out with movement, coughing, or bowel movements
- You feel persistent dragging or descent of the prolapse
- You can easily remove it without folding
- Your provider notes the device is rotating or shifting on exam
↓Consider sizing down if…
- You feel pressure, pinching, or pain when seated or walking
- Removal is difficult or causes discomfort
- You experience new urinary urgency or difficulty voiding
- The vaginal wall shows redness or irritation at follow-up
Common sizing mistakes to avoid
Ordering by guesswork before any fitting
Pessaries cannot be sized accurately from external measurements or symptoms alone. A clinical fitting exam is required for first-time users.
Choosing "in between" sizes
Each size step is roughly 6–7 mm. There is no half-size; if you're between 4 and 5, your provider will trial both and pick the more retentive comfortable fit.
Sizing up "just to be safe"
An oversize pessary causes pressure, urinary symptoms, and tissue irritation. The smallest size that holds reliably is the right size.
Not re-checking fit annually
Vaginal anatomy changes with age, weight, and surgery. A yearly fit check is recommended even if your current pessary feels fine.
Order your size
Once your provider has confirmed your size, order direct from SciMed at manufacturer pricing. Same-day US dispatch on orders placed before 2 PM ET, in plain discreet packaging. All SciMed pessaries are FDA 510(k)-cleared Class II medical devices regulated under 21 CFR 884.5350 (FDA Product Code HHN).
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Clinical references
All clinical claims on this page are referenced to the primary medical sources below. The citations are linked inline throughout the article above.
- Cooley LE, Jones DR. Vaginal pessaries for pelvic organ prolapse. Canadian Family Physician, 2007. PMC1949074. (Source of the "approximately 80% of grade 1 and 2 prolapse treatable by ring pessaries" finding.)
- International Urogynecological Association. Expert Opinion: Vaginal Pessaries in the Management of Pelvic Organ Prolapse. IUGA Spotlight v16.1. (Source of "ring may fit up to 70% of women" and silicone hypoallergenic/autoclavable properties.)
- Pelvic, Obstetric and Gynaecological Physiotherapy (UK). Pessary Types Guide, April 2021. (Source of pessary categorization and trial-and-error fitting protocol.)
- University of Colorado Anschutz. Pessary patient information. CU Anschutz urogynecology. (Source of "trial-and-error like trying on shoes" framing.)
- U.S. Food & Drug Administration. 21 CFR 884.5350 — Pessary. eCFR. (FDA Product Code HHN regulatory classification for ring pessaries.)
- Brigham and Women's Hospital, Department of Urogynecology. Pessary instructions for patients. Harvard-affiliated teaching hospital. (Additional clinical patient-instruction reference.)
Frequently asked questions
What size pessary do most women use?
In US gynecology practice, sizes 3, 4, and 5 (64–76 mm) are the most commonly fitted ring pessaries. Younger women without prior vaginal delivery often fit smaller; women post-vaginal-delivery and post-menopausal often fit larger.
Can I fit myself at home?
No. First-time pessary fitting requires a clinical pelvic exam and a fitting trial. Self-fitting risks an incorrect size that causes pressure injury, urinary symptoms, or pessary expulsion.
What's the difference between with-support and without-support?
The with-support ring includes a thin silicone membrane that helps support the bladder in patients who have a coexisting cystocele (anterior wall prolapse). Without-support is a simple open ring used when there is no cystocele.
Will my size change over time?
It can. Weight change of 10 lb or more, pelvic floor physical therapy, vaginal estrogen therapy, or pelvic surgery can all change pessary fit. A yearly fit check is recommended.
Is the size on the package the same as the diameter?
The size number (0–9) is a clinical convention. The actual outer diameter in millimeters is printed on each unit's pouch alongside the size number, lot, and expiration date.
What if my fitting size isn't in stock anywhere else?
SciMed stocks all 10 sizes (0–9) continuously. Most US suppliers stock five or six common sizes. If your provider has fitted you to a less-common size, we can ship same business day.
Is SciMed sizing the same as Milex or Bioteque?
Yes. Ring pessary sizing is standardized across FDA-cleared US manufacturers — size 3 is 64 mm, size 4 is 70 mm, size 5 is 76 mm, and so on. If your provider fitted you to a Milex or Bioteque size, the equivalent SciMed size is the same number and diameter.
What if I'm between two sizes — which should I choose?
Being between sizes is common (for example, a size 3 slips when you bear down but a size 4 feels tight). The rule of thumb: keep the smallest size that still holds reliably during a cough/Valsalva test — the smallest retentive size is the correct one, because an oversize ring causes pressure and urinary symptoms. If a smaller ring keeps slipping, the with-support version can stabilize a ring that would otherwise be borderline. When you're unsure, the 3-Size Right-Size Pack lets you trial three adjacent sizes at home.
Need help finding your size?
Our team can confirm sizing details, provide clinical references, and ship to your provider's office on request.
Email our teamRelated Guides — New for 2026
Continue reading on these closely related topics:
- Ring Pessary Size 3 (64 mm) — Who It Fits and How to Choose
- Ring Pessary Size 4 (70 mm) — The Most Commonly Fitted Size
- Ring Pessary Size 5 (76 mm) — Who Needs It and How to Confirm Fit
- Ring Pessary After Hysterectomy — Complete Patient Guide
- How Often Should You Replace a Ring Pessary?
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