What 1,800+ Real Pessary Fittings Tell Us About Sizing

Reviewed by SciMed Store Clinical Team · Published August 19, 2026

Choosing a pessary size is the single most anxious moment for a first-time patient. Most sizing advice online is generic or based on small clinical studies. We had something different: the real distribution of what actually gets ordered and kept, across nearly 1,500 US patients over four years — so we opened our own data.

Everything below comes from SciMed's own order records, aggregated and anonymized. No individual is identifiable. This is descriptive commercial data — not a clinical trial, and not a substitute for a professional fitting.

The headline finding: ring pessary sizing follows a clean bell curve. Size 4 is the single most common fit (more than 1 in 4 women), and sizes 3–5 together account for two-thirds of all fittings.

Methodology

• Source: SciMed Store Shopify order records.
• Period: January 2022 – August 2026.
• Population: US orders for silicone ring pessaries (with- and without-support), fitting packs, and combos.
• Totals: ~1,850 individual pessary rings dispensed across ~1,480 US orders (about one patient per order).

The size analysis below focuses on our flagship Ring Pessary With Support (sizes 0–8), where n = 1,214 individually sized rings.

The size distribution

Two numbers to remember: Size 4 = 27.5% (more than one in four patients). Sizes 3–5 = 66.5% of all fittings. The without-support ring (sizes 0–9) shows the same bell-shaped pattern across its 372 rings.

How often patients keep their pessary

Across roughly 1,480 US patient orders since 2022, SciMed recorded only 3 refunds — under 0.3%. The overwhelming majority of patients kept the pessary they ordered. (We are now instrumenting exchange reasons systematically so a future edition can report exchange-rate by size.)

What the curve means clinically

The distribution mirrors pelvic anatomy across the adult female population. A ring pessary is sized to the vaginal introitus and length; most women cluster in the middle of the range, with fewer at the extremes. For a first-time patient: if you have no idea where to start, you are statistically most likely to need a size 3, 4, or 5.

The Fitting Pack

For patients who can't get an in-person fitting, SciMed offers a 3-size Fitting Pack for home trial. It bundles the three most-likely sizes (typically 3–4–5) so most first-time patients find the correct fit in the box.

How this compares to published sizing literature

Our distribution is consistent with the clinical consensus that mid-range ring pessary sizes fit the majority of patients, with size selection following a normal distribution around the middle of the range — as reflected in ACOG Practice Bulletin 214 (Pelvic Organ Prolapse). We invite clinicians to compare our aggregate distribution against their own fitting records.

Five takeaways for first-time patients

1. Start in the middle. Sizes 3–5 fit two-thirds of women; size 4 is the most common single fit.
2. A ring pessary should be comfortable, not tight. Constant pressure usually means it's too large.
3. If it slips or falls out, it's usually too small — size up before giving up on the device.
4. Consider a Fitting Pack if you can't get an in-person fitting.
5. Re-check your size after big changes — childbirth, significant weight change, or menopause can change the fit.

This is general information, not medical advice. Talk to your OB-GYN or pelvic health provider about your individual fit, and follow ACOG guidance on pessary care.

Limitations & a call for feedback

This is commercial order data, not a clinical study — it reflects what patients ordered and kept, not clinician-verified fittings. Figures are US aggregate. If you're a clinician or researcher who fits pessaries, we'd welcome a comparison with your own aggregate data — email store@scimedstore.com. We plan an updated edition in Q1 2027 with exchange-rate by size.

SciMed Store is a US supplier of FDA-cleared silicone ring pessaries and medical devices. Data compiled from Shopify order records, 2022–2026.