A leaking menstrual cup doesn't necessarily mean you've chosen the wrong cup. Leaks can happen if the cup hasn't fully opened, it isn't positioned to collect flow from your cervix, it has become full or the fit isn't quite right for your anatomy. Small leaks can also be residual menstrual blood left in the vaginal canal after insertion. Here's what to check and what to try next.
Key takeaways
- Check that your cup has fully opened after insertion.
- Make sure your cup is positioned to collect flow from your cervix.
- If the cup is full, empty it more frequently, particularly on heavier days.
- Consider the cup's length, diameter, shape, firmness and capacity when assessing fit.
- A small amount of blood soon after insertion may simply be blood already in the vaginal canal.
- If you keep leaking despite troubleshooting, another cup or a different period product may suit your anatomy and flow better.
Table of contents
- Why is my menstrual cup leaking?
- 1. Your cup hasn't fully opened
- 2. Your cup isn't positioned over your cervix
- 3. Your cup is full
- 4. You're seeing residual blood rather than a cup leak
- 5. The cup's size or shape may not suit you
- 6. Your cup's holes need cleaning
- What if my menstrual cup keeps leaking?
- When should I seek medical advice?
- Frequently asked questions
Why is my menstrual cup leaking?
The first thing to work out is when the leaking happens and how much blood you're seeing.
A few streaks shortly after inserting your cup can be residual blood already in the vaginal canal. If leakage starts after several hours, an overflowing cup may be more likely. If you leak soon after insertion, check whether the cup has opened fully and whether it is positioned to collect flow from your cervix.
Cup fit also matters. Menstrual cups come in different lengths, diameters, shapes, firmness levels and capacities, so a cup that works well for one person may not suit another person's anatomy or flow.
Research on menstrual cups supports their use as a period product, but studies also show that learning to use one can take time. A 2019 systematic review of 43 studies involving 3,319 participants found that direct-comparison studies reported leakage that was similar to or lower than disposable pads or tampons. The researchers also noted a familiarisation period over several menstrual cycles in many studies. Only a small proportion of the included studies were considered moderate-to-high quality, so the evidence should be interpreted with some caution.
1. Your cup hasn't fully opened
A menstrual cup needs to open after insertion so its rim can sit against the vaginal walls and collect menstrual flow.
After inserting your folded cup, gently feel around the outside of the cup with a clean finger. If you can feel a significant dent or folded section in the rim, it may not have opened completely.
You can try:
- gently running a finger around the rim to help it open
- trying a different fold
- gently rotating the base if this is comfortable and recommended for your cup
- removing and reinserting the cup if it still hasn't opened
You don't need to force a full rotation or a particular technique. Different cup designs behave differently.
If you're experimenting with folds, see Period Shop's guide to different menstrual cup folds.
2. Your cup isn't positioned over your cervix
Your cervix is the lower part of the uterus that extends into the vaginal canal. Menstrual flow passes through the cervix before entering the vagina.
For a menstrual cup to collect that flow, the cup needs to be positioned in a way that works with the location of your cervix. If your cervix sits beside the cup rather than over it, blood can flow around the cup instead of into it.
Your cervix can also change position during your cycle, so the position that works on one day may feel different on another.
If you're unsure where your cervix sits, Period Shop's guide to measuring your cervical position can help you understand how cervix height may affect cup length and fit.
Don't worry if your cup naturally settles a little higher or lower than where you first inserted it. The important thing is that it remains comfortably inside the vagina and works with your anatomy.
3. Your cup is full
A menstrual cup can leak simply because it has reached its capacity.
This is more likely on heavier-flow days. You may find that your cup lasts much longer overnight or towards the end of your period than it does during your heaviest day.
If the cup is consistently full when you experience a leak, try emptying it more frequently rather than assuming the cup isn't sealing properly.
Australian TGA guidance requires menstrual cups supplied in Australia to include instructions specifying a maximum duration of use of no more than 12 hours. Your particular manufacturer may recommend a shorter interval, so always follow the product instructions.
If your cup is overflowing regularly, you may also want to compare its capacity with other cup options. Remember that capacity is only one part of fit. A higher-capacity cup may be longer, wider or firmer and therefore may not be more comfortable for your anatomy.
4. You're seeing residual blood rather than a cup leak
Not every small amount of blood on your underwear means the menstrual cup has leaked.
Blood can remain in the vaginal canal below the cup after you insert it. That blood may come out shortly afterwards, particularly when you stand up, walk around or use the toilet.
Try wiping around the vulva after inserting your cup and see whether the spotting stops.
If you continue seeing blood after the initial few minutes, check the cup itself when you remove it. If it is mostly full, overflow may be the issue. If it contains very little blood, check whether it opened properly and whether your cervix is positioned over the cup.
5. The cup's size or shape may not suit you
There isn't one menstrual cup size that works for everyone.
Cup fit can be affected by:
- cervix height
- cup length
- cup diameter
- cup shape
- firmness
- stem design
- pelvic anatomy
- menstrual flow
- personal comfort preferences
A cup that is too short may not sit where you need it to. A cup that is too narrow may not fit securely for your anatomy. A cup that is too long or wide may be uncomfortable or difficult to position.
Age or whether you've given birth should not be used as the only way to choose a cup. Manufacturer size guides can be useful starting points, but anatomy and personal fit matter too.
If you've ruled out insertion and positioning problems and your cup still leaks, compare its dimensions with other options in the Period Shop menstrual cups comparison chart.
You can compare factors such as length, diameter, capacity and firmness rather than choosing based on the label “small” or “large” alone.
6. Your cup's holes need cleaning
The small holes around the rim of a menstrual cup help the cup open and function as designed.
If they become blocked with menstrual fluid or residue, clean them according to the manufacturer's instructions before reinserting the cup.
Rinse the holes thoroughly and check that they are clear. Avoid using sharp objects such as needles or toothpicks unless the manufacturer specifically recommends a particular cleaning method for your cup, as sharp objects could damage the material.
What if my menstrual cup keeps leaking?
If you've checked the opening, position, capacity and fit and you're still leaking, it may simply be that this particular cup isn't the right match for your anatomy or flow.
That's not a failure on your part.
You could try a different cup length, diameter, shape or firmness. You can browse Period Shop's menstrual cups to compare other options. You may also decide that a menstrual disc, period underwear, reusable pads or another period product suits you better.
If you're new to cups, give yourself some time to learn the technique, but you don't need to persist with a product that isn't working for you.
For more detailed troubleshooting, read How to Use a Menstrual Cup.
When should I seek medical advice?
Occasional leakage from a menstrual cup is usually a product-use or fit issue, but persistent or unusual bleeding should not automatically be blamed on the cup.
Seek advice from a qualified healthcare professional if you have unusually heavy bleeding, bleeding between periods, significant pelvic pain or other symptoms that concern you.
If you develop symptoms such as a sudden high temperature, vomiting, diarrhoea, dizziness, confusion, muscle aches or a widespread red rash while using a menstrual cup, remove the cup and seek urgent medical care. Toxic shock syndrome is rare but serious and has been associated with menstrual cup use.
Frequently asked questions
Why is my menstrual cup leaking but not full?
If your cup isn't full, check whether it has opened completely and whether your cervix is positioned over the cup. A small amount of blood shortly after insertion can also be residual blood already in the vaginal canal.
Why does my menstrual cup leak at night?
Night-time leaks can happen if your cup becomes full, particularly on a heavy-flow day. Check the cup's capacity and how full it is when you remove it. If the cup isn't full, review its opening and position.
Why does my menstrual cup leak when I sit down?
Changes in body position can alter how a cup sits, but sitting itself should not automatically cause a leak. Check that the cup is fully open and that its length and shape suit your anatomy. If the base or stem is uncomfortable when sitting, the cup may also be a poor fit.
Can a menstrual cup overflow?
Yes. A cup can leak when it reaches its capacity. If this happens regularly, you may need to empty it more frequently or consider whether a higher-capacity cup could suit your anatomy and flow.
Does a menstrual cup need to be rotated?
Not necessarily. Some people find gentle rotation helps their cup open, but there is no need to force a 360-degree rotation. Follow your manufacturer's instructions and use whatever technique allows your cup to open comfortably.
How long does it take to get used to a menstrual cup?
It varies. Some people become comfortable quickly while others need several cycles to learn insertion, positioning and removal. A 2019 systematic review found that familiarisation over several cycles was reported in multiple studies.
The bottom line
A leaking menstrual cup doesn't automatically mean you've chosen the wrong product. Start by checking whether it has opened fully, whether it is positioned to collect flow from your cervix and whether it has become full. If those things look right, review the cup's length, diameter, shape, firmness and capacity.
If you want to compare those features side by side, use the Period Shop menstrual cups comparison chart to explore different starting options.