Why Is My Menstrual Cup Leaking? 6 Causes and How to Fix Them

If your menstrual cup is leaking, when the leak happens tells you a lot about the cause. Leaking immediately after insertion usually points to incomplete opening or cervix misalignment. Leaking after several hours is more often a capacity issue. And if a cup that worked for years suddenly starts leaking — especially after childbirth — changes in cervix position, pelvic floor support, or fit may be involved.

If you use a DivaCup specifically, its length may also matter if you have a low cervix. Below is a quick diagnostic table, then the six real causes and what to check for each.

Menstrual Cup Leaking: Quick Diagnostic Table

The 6 Real Causes of a Leaking Menstrual Cup

1. The Cup Didn't Open Properly

The most common cause, especially in the first cycles. The cup has to unfurl fully and seal against the vaginal walls. If it stays partially folded, fluid bypasses it.

How to check: run a clean finger around the base — you should feel a round or oval shape, free of indentations.

What to try: contract your pelvic floor, push the cup upward, then relax and pull it down slightly. You'll often feel it open. See our how to use guide for step-by-step insertion.

2. Cup Size, Length, or Firmness Doesn't Match Your Anatomy

A cup that's too long leaves no room for the cervix. A cup that's too soft may not stay open against a strong pelvic floor; a cup that's too narrow may not seal.

Factors that decide your fit:

What to try: use the Cup Finder quiz or the size guide to match your anatomy rather than the cup you happen to own.

Cervix height — measured in finger phalanges
Flow volume
Vaginal births
Pelvic floor function

3. Insertion Too Deep or Misaligned With the Cervix

The cup should sit around the cervix, not above it. If the cervix ends up outside the rim, blood bypasses the cup entirely — which looks and feels exactly like a leak.

What to try: insert a clean finger along the cup wall. If you feel the cervix outside the rim, pull the cup down slightly and rotate it.

4. Blocked Suction Holes

The small airholes near the rim create and release the seal. Blocked holes can mean a weaker vacuum and leaks.

What to try: clean the holes at every rinse, and check them between cycles. See the complete cup cleaning guide.

5. Pelvic Floor Involvement

Pelvic floor muscles influence how a cup sits and how well it stays in place. Both reduced support and an overactive, poorly coordinated pelvic floor can be involved in leaking or slipping.

If leaking or slipping comes with urinary leakage, pelvic pressure, pain, or other pelvic-floor symptoms, consider a pelvic-floor assessment. A pelvic floor can be weak, overactive, or poorly coordinated — and the approach is different for each. Our article on tight vs weak pelvic floor explains why generic strengthening advice isn't always the right answer, and the 1-minute pelvic floor quiz can help you see which pattern fits your symptoms.

6. Capacity and Daily Life

Heavy days can outrun any cup. Exercise, sex, and bowel movements can also shift a cup mid-wear.

What to try: empty proactively on heavy days. If your body has changed (postpartum, weight change, perimenopause), re-check your fit — the cup that fit two years ago may not fit now.

Why Is My DivaCup Leaking?

DivaCup is one of the longer cups on the market. Per DIVA's official sizing guide, Model 0 measures about 65 mm in total length and Models 1 and 2 about 66 mm, stem included.

For comparison, measured the same way, Leia Cup Small is 61 mm total length (49 mm body without the stem) with a 45 mm rim diameter. When you compare cups, make sure you're comparing like with like — body length without stem against body length without stem, or total against total. A number like 45 mm is often a diameter, not a length.

Why length matters: if your cervix sits low, it descends into the cup and occupies part of the collection volume, so the cup fills sooner and the seal is easier to break. A longer cup also has less room to sit comfortably below a low cervix. If your cervix sits mid or high, DivaCup's length is unlikely to be the problem, and the cause is more likely opening, alignment, or capacity.

Why Did My Menstrual Cup Suddenly Start Leaking After Childbirth?

This is one of the most common "it used to work" scenarios. After a vaginal birth, cervix position can change, vaginal wall tone and support can change, and pelvic floor coordination often changes too — sometimes temporarily, sometimes longer term.

Practically, that means three things worth rechecking rather than assuming the cup is faulty:

If your cervix now sits lower, a shorter cup body usually helps more than a different folding technique. Read more in our postpartum cup fit guide.

Re-measure your cervix height during your period; it may sit lower than it did before.
Reassess capacity — postpartum cycles are often heavier for a while.
Notice other symptoms. Leaking with urinary leakage, heaviness or pressure is a reason to get a pelvic-floor assessment rather than to buy a firmer cup.

Why Does My Menstrual Cup Leak When I Sneeze or Exercise?

Coughing, sneezing, jumping and heavy lifting all raise intra-abdominal pressure. That pressure pushes down on the pelvic floor and on whatever is sitting in the vaginal canal. If the seal is marginal, or if the cup is already near capacity, that's when a leak shows up.

What to check:

Is the cup actually full? Pressure leaks are often capacity leaks in disguise.
Is the seal complete? Do a finger sweep around the base after inserting.
Does the cup move down over the day? Downward migration suggests a fit or support issue rather than a technique issue.
Do you also leak urine when you sneeze or run? That points to the pelvic floor, and it's worth an assessment rather than self-prescribed exercises.

When the Problem Is Fit, Not Technique

If you've checked insertion, capacity and cervix position but the cup still slips or leaks, the issue may be fit rather than technique. This is especially relevant if you have a low cervix or noticed changes after childbirth.

Leia Cup was designed for exactly these fit challenges: a shorter body (49 mm in Small, 61 mm total length including the stem), an asymmetric rim shaped to sit around a low cervix, and medical-grade silicone chosen to hold its shape without excess pressure. Sizes go up to Large for bodies after multiple vaginal births.

If you'd like a size recommendation based on cervix height, flow and birth history, the 60-second Cup Finder quiz walks through it, or you can compare specs directly on the Leia Cup product page and the low-cervix comparison chart.

FAQ: Menstrual Cup Leaking

Why is my DivaCup leaking all of a sudden?

The two common triggers are a change in cervix position (postpartum, perimenopause, or simply this cycle) and a change in pelvic floor function. DivaCup's total length is around 65–66 mm per DIVA's sizing guide, which works best when the cervix sits mid or high; if yours now sits lower, a shorter cup body may fit better.

Can a menstrual cup leak even when placed correctly?

Yes. A well-inserted cup can still leak if it's the wrong length or firmness for your anatomy, or if your cervix takes up part of the collection volume.

Do menstrual cups leak overnight?

They can. Overnight leaks usually come down to a seal that didn't fully form at bedtime, or flow that exceeded the cup's capacity. Emptying right before bed and using a higher-capacity cup both help.

How long does it take to get used to a menstrual cup?

Often a few cycles. A systematic review of 43 studies found that leakage was comparable to or lower than pads and tampons, and that many users needed several cycles of practice before they were consistently comfortable.

Key Takeaways

button:Find your size in 60 seconds

When the leak happens is the fastest clue to why it happens.
Most leaks come down to opening, alignment, capacity or fit — not user error.
Compare cups like with like: body length to body length, total to total. A 45 mm figure is usually a diameter.
New leaking after childbirth is a reason to re-measure cervix height and reconsider fit.
Leaking alongside urinary leakage, pressure or pain is worth a pelvic-floor assessment.

Sources

van Eijk AM, Zulaika G, Lenchner M, et al. Menstrual cup use, leakage, acceptability, safety, and availability: a systematic review and meta-analysis. The Lancet Public Health, 2019 — review of 43 studies on leakage, safety and acceptability. Read the review30111-2/fulltext)
Prospective pelvic-floor study of menstrual cup users (n=10). Very small sample — treat as preliminary rather than conclusive.
Competitor cup measurements cited above are taken from each manufacturer's own published sizing specifications.