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6 Top Reasons Why Your Menstrual Cup Leaks

Jan 22, 2024

When your menstrual cup fits correctly, it works quietly in the background of your life. When it leaks, it becomes frustrating fast. You want to rely on your cup without constant worry.

Here are the six most common reasons your menstrual cup leaks and how to stop it.

1. The Diameter Is Too Small to Make a Seal

The most common cause of menstrual cup leaks is an incorrect diameter. Even with a light flow, your cup needs enough width to create a seal against your vaginal walls.

MeLuna offers four different diameters, making it easy to size up or down.

If you’re switching from another brand like Diva, Lena, Lunette, Saalt, or Flex, check our visual comparisons:

Menstrual Cup Diameter Comparison

Menstrual Cup Diameter Comparison

Switching Menstrual Cup Brands

These guides show how MeLuna cup sizes compare to other brands.

Fix:
Choose a cup with enough diameter to make a solid seal. If your MeLuna cup isn’t the right fit, the MeLuna USA Guarantee helps you find your perfect size. You keep your current cup and receive a second one at 50% off to fine-tune your fit.

2. The Cup Height Doesn’t Match Your Cervix

Many first-time users choose the smallest cup to start, but if your cervix is average or high, a short cup can tip and leak. MeLuna Shorty cups are designed only for users with a very low cervix who cannot wear standard-length cups comfortably.

Fix:
Pick a cup height that matches your anatomy. Avoid ordering a MeLuna Shorty unless you have a confirmed low cervix.

Learn more here: Menstrual Cups for Low Cervix.

If your first choice wasn’t perfect, the MeLuna USA Guarantee lets you try another size at 50% off.

3. Your Cup Is Too Soft for Your Activity Level

If your menstrual cup is very soft or you use your core muscles often, it can get compressed and start leaking. Not every activity requires a firm cup, but strong core engagement during workouts like Pilates or strength training can cause a soft cup to lose its seal.

Fix:
Extra soft cups, often labeled “sensitive,” can be difficult to seal. For most users, the Classic MeLuna firmness works best.

If you do activities that involve heavy core engagement, try the MeLuna Sport.

Some people prefer owning more than one cup, one for everyday use and one for sports. Read more in our post about using multiple cups or visit our guide on Menstrual Cups for Sport and Exercise .

woman working out during her period

4. The Cup Isn’t Fully Unfolding

Sometimes a menstrual cup stays partially collapsed after insertion, which prevents it from sealing properly.

TPE cups naturally take on a slightly oval shape once inside, which is normal and does not cause leaks. Learn more in our FAQ .

Fix:
Try a fold that helps your cup pop open, such as the Punch-Down Fold. After inserting, twist the cup gently or push it higher, then let it settle to form a seal.

If leaks continue, you can:

Try one diameter smaller, or
Choose a firmer cup material.

The MeLuna USA Guarantee lets you order a second cup at 50% off to fine-tune your fit.

5. The Cup Isn’t Positioned Correctly

Cervix position plays a big role in menstrual cup leaks. Your cervix may sit lower at the start of your period and higher toward the end. It’s also not always centered.

If your cup sits past or above the cervix, fluid can bypass the cup and cause leaks.

Fix:
Locate your cervix by gently feeling for a small, round bump that feels like the tip of your nose. Position your cup so it sits just below the cervix, not above it.

Additional Tips for Correct Cup Placement:

If you have a sensitive cervix, place the cup slightly lower to reduce cramping or discomfort.
Avoid placing the cup directly on the cervix, which can reduce capacity and cause leaks.
Hormonal changes affect cervix height and firmness, so adjust placement as needed.
The vaginal canal angles toward your back, so insert the cup toward your tailbone, not straight up.
Check cervix height throughout your cycle to maintain a comfortable and effective fit.

menstrual cup inserted wrong

6. The Cup Has Reached Its Capacity

Every menstrual cup will leak once it’s full. Shorty cups hold less because of their reduced height.

If you have a heavy flow and a low cervix, you may need to empty your MeLuna Shorty more often to avoid leaks.

Fix:
A shorter cup has a smaller volume, so it’s normal to need more frequent emptying if your flow is heavy. This is a normal part of using a low-cervix menstrual cup.

volume of a menstrual cup affects capacity

Still Leaking? Take the Menstrual Cup Quiz

If your menstrual cup leaks even after troubleshooting, take the Menstrual Cup Quiz.

The quiz helps identify the best size, shape, and firmness for your anatomy and activity level. You’ll find a cup that fits your body comfortably and prevents leaks for good.

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