Ring Pessary Size Chart: Which Size Is Right for You?
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If you've been prescribed a ring pessary, one of the first questions you'll ask is: which size do I need? Getting the right fit is critical — a pessary that's too small will fall out, and one that's too large will be uncomfortable. This quick-reference guide gives you the complete ring pessary size chart, how OB/GYNs fit pessaries, and what to expect.
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Shop by Size →What Is a Ring Pessary?
A ring pessary is a small, flexible silicone device inserted into the vagina to support the pelvic organs. It's commonly used to treat pelvic organ prolapse (POP) and stress urinary incontinence. Ring pessaries come in two styles: without support membrane (an open ring, best for prolapse alone) and with support membrane (a solid diaphragm across the ring, for prolapse with coexisting cystocele or SUI).
Order our 3-Size Right-Size Pack ($129.99) — 3 consecutive sizes to trial at home. Save $19.98 vs 3 singles, keep the fit as backups.
Ring Pessary Size Chart
Ring pessaries are numbered 0 through 9, with each size corresponding to a specific outer diameter. This is the standard reference used by clinicians and manufacturers (SciMed, Milex, Bioteque — sizing is standardized):
| Size | Diameter (mm) | Diameter (inches) | Availability at SciMed |
|---|---|---|---|
| 0 | 44 mm | 1.75″ | With + Without Support |
| 1 | 51 mm | 2.00″ | With + Without Support |
| 2 | 57 mm | 2.25″ | With + Without Support |
| 3 ⭐ | 64 mm | 2.50″ | With + Without Support |
| 4 ⭐ | 70 mm | 2.75″ | With + Without Support |
| 5 ⭐ | 76 mm | 3.00″ | With + Without Support |
| 6 | 83 mm | 3.25″ | With + Without Support |
| 7 | 89 mm | 3.50″ | With + Without Support |
| 8 | 95 mm | 3.75″ | With + Without Support |
| 9 | 102 mm | 4.00″ | Without Support only |
⭐ Sizes 3, 4, and 5 fit approximately 60–70% of patients in clinical practice. If you haven't been fitted, your clinician will likely start with size 4.
How Is Pessary Size Determined?
A ring pessary must be fitted by a healthcare provider — your OB/GYN, urogynecologist, or pelvic floor nurse practitioner. Here's what the fitting process looks like:
- Pelvic exam: Your provider assesses the degree of prolapse and measures the vaginal canal width and depth.
- Trial fitting: The provider inserts a trial ring of their estimated size. The correct fit allows a finger to pass between the ring and vaginal wall, and the patient can walk, cough, and bear down without it dislodging or causing discomfort.
- Confirmation: You'll be asked to empty your bladder normally to confirm the pessary doesn't obstruct urination.
Many clinics use a pessary fitting kit — a set of 5–7 trial rings in graduated sizes — to find the right fit in one visit. SciMed offers a 7-size Clinical Fitting Kit ($289.99) designed for OB-GYN and urogynecology practices.
Factors That Affect Your Pessary Size
- Parity: Women who have had vaginal deliveries typically need a larger size.
- Degree of prolapse: More significant prolapse often requires a larger ring.
- Vaginal tone: Decreased estrogen (postmenopause) can affect tissue laxity and sizing needs.
- Activity level: Very active patients may need a slightly larger size to remain in place during exercise.
- Weight change: Gaining or losing 15+ lbs can shift correct size by one.
Signs Your Pessary May Be the Wrong Size
- Too small: Falls out when straining, walking, or having a bowel movement; prolapse symptoms persist.
- Too large: Pressure, discomfort, or difficulty urinating; vaginal irritation or discharge.
- Wrong style: A ring without support may not provide adequate support for Stage III+ prolapse.
Can I Order a Replacement Without a New Fitting?
Yes. Once your clinician has determined your correct size, you can reorder the same size without returning for another fitting. SciMed offers ring pessaries in all sizes (0–9) with free US shipping. If you're unsure of your size, consider the 3-Size Right-Size Pack ($129.99) — 3 consecutive trial sizes to find your fit at home under clinician guidance.
Frequently Asked Questions
What is the most common ring pessary size?
Sizes 3, 4, and 5 (64–76 mm) are fitted most frequently in clinical practice. Size 4 (70 mm / 2.75″) is often the starting size for a new fitting.
Is SciMed sizing the same as Milex sizing?
Yes. Ring pessary sizing is standardized across all FDA-cleared manufacturers — size 4 is 70 mm regardless of brand. If your provider sized you for a Milex or Cooper Surgical ring, the equivalent SciMed size is the same number.
How do I know if my ring pessary fits correctly?
A well-fitted ring pessary stays in place during normal activities, allows you to urinate freely, and doesn't cause pain or pressure. You should barely notice it once properly placed.
How often should I replace my ring pessary?
Most clinicians recommend replacement every 12–24 months for silicone ring pessaries. Replace sooner if the device shows signs of wear, discoloration, or persistent odor after thorough cleaning.
Can I order a pessary without a prescription in the US?
Yes. Ring pessaries are FDA Class II medical devices that can be purchased without a prescription in the United States. However, initial sizing by a qualified provider is strongly recommended.
Shop FDA-Cleared Pessaries — All Sizes →
Related Reading:
Related Guides
- Size 3 (2.50 in / 64 mm) Detailed Guide
- Size 4 (2.75 in / 70 mm) — Most Fitted Size
- Size 5 (3.00 in / 76 mm) Detailed Guide
- Sizing After a Hysterectomy
- Pessary Cost Without Insurance (2026)
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