How to pick your menstrual disc size?

Menstrual discs are becoming an increasingly popular period product as more brands develop reusable versions that are easier to insert, more comfortable to wear, and better suited to everyday lifestyles. Although menstrual discs have actually existed since the 1990s, the rise of newer designs has encouraged more people to give them a try — especially those looking for a convenient and more sustainable alternative that helps reduce daily waste. And if you’re wondering, “How do I choose the right size? Which type should I use?” — don’t worry. Finding the right menstrual disc for your body is much simpler than it may seem.This article will help you understand how to choose a menstrual disc in an easy and approachable way, so you can start using one with confidence and comfort.

Choosing a menstrual disc is different from choosing a traditional menstrual cup. Menstrual cups are typically selected based on pelvic floor muscle tightness, as well as diameter and length. 

What disc size is right for me?

You should start by measuring your cervix. Your cervix height and position does change throughout the menstrual cycle, and it’s best to measure your cervix height during the start or towards the end of your period for the most accurate measurement. 

You can measure your cervix by inserting your finger and feeling around -- your cervix will feel round and have the same firmness as the tip of your nose during menstruation . Measure how deep your finger fits inside your vagina.

A low cervix = 44mm or lower from your vaginal opening to the tip of the cervix.

An Average Cervix = 45mm – 55 mm  from your vaginal opening to the tip of the cervix.

A High Cervix = 55mm  or higher from your vaginal opening to the tip of the cervix. If you can’t reach your cervix you can safely assume it’s high, but for accuracy, you may want to measure your entire finger.

Have a high cervix

For people with a high cervix, softer menstrual discs such as the Softie Disc may not be the best option. When inserting a soft disc, the rim can collapse or bend out of shape, which may prevent it from properly covering the cervix.

Instead, we recommend going for firmer discs with a more structured rim, such as the Sister Disc or Signature Disc. Their firmer shape stays stable during insertion, allowing the disc to sit securely and cover the cervix more effectively.

Have an Average or Low Cervix

For people with a medium or relatively low cervix, softer menstrual discs with a smaller and flatter design are often more suitable. These types of discs are generally easier to insert and adapt more comfortably to the body compared to firmer models. We recommend VVomen’s  Sister Disc for this cervix type.

Have a Tilted Cervix

If your cervix is retroflexed (facing the back wall of the vagina) a disc may be harder to use or impossible. If the disc cannot get under and past the cervix to properly tuck, you could experience leaking. Most people only know they have a retroflexed uterus through being told by a care provider. If there is enough space for the disc to slip under the cervix it may still work; you will need to "scoop" the disc around the cervix during insertion, which is hard to do when you can't see inside your body. Menstrual cups, which are worn below the cervix, are usually less affected by tilts of any direction for this reason.

Why does my menstrual disc leak?

Leakage while wearing a menstrual disc is usually related to the size, positioning, or how long the disc has been worn.

If the menstrual disc is “too large,” you may experience the following symptoms:

• The disc may pop out from behind the pubic bone

• A feeling of pressure, heaviness, or like the disc is slipping out

• Leaking when coughing, squatting, or using the bathroom

• Frequent unintentional auto-dumping

If the menstrual disc is “too small,” you may experience the following symptoms:

• The disc may not fully cover the cervix

• Menstrual blood may flow around the disc instead of collecting inside it

• The disc may rotate or shift easily

• Leakage may occur during heavier flow days

Photo credit 

Common causes of leakage (other than size)

The cervix is not positioned inside the menstrual disc.

This is actually the number one cause of leakage. Sometimes the disc sits beside the cervix instead of underneath it, which allows menstrual blood to flow past the disc instead of being collected inside it.

How to check:

After inserting the disc, try using your finger to feel around the rim of the disc.

• If you can feel your cervix sitting inside the basin of the disc, the placement is correct.

• If your cervix is positioned to the side of the disc, there is a high chance of leakage.

The disc rim is not staying securely behind the pubic bone.

The front rim of the disc should tuck and lock behind the pubic bone. If it slips out easily, the disc may be too large or the rim may be too soft for your anatomy.

The shape and firmness of the menstrual disc may not be compatible with your anatomy.

• People with a lower cervix often do better with softer discs, 

• People with a higher cervix may find firmer and more structured discs more suitable.

Experiencing leaks while using a menstrual disc does not necessarily mean you are using it incorrectly. In most cases, leakage happens because the disc size or positioning is not yet the right fit for your anatomy. Remember, every body is different. The best menstrual disc is not the one that works for someone else, but the one that fits your body comfortably and securely.

Other Considerations

The menstrual disc market is still relatively small, which means the range of available options is somewhat limited. However, beyond size or diameter, there are also subtle design details that can influence your decision.

That said, many of these factors can only truly be understood through actual use. Ultimately, choosing the right disc comes down to your individual anatomy and personal comfort.

Can I be sure a disc will work before buying one?

Everyone’s body is different. While measuring your cervix height is one of the most helpful ways to choose the right disc size, it doesn’t guarantee a perfect fit 100% of the time.

Another important factor is practice. Sometimes what seems like a sizing issue may actually come from incorrect placement.

The most common mistake is not positioning the disc properly behind the pubic bone — which is a key step in preventing leaks.