The best menstrual cup for a heavy flow is one with enough capacity for your heaviest days and a rim that seals well, and you empty it more often than on lighter days. With Lunette, that is Size 2: it holds 30 ml and is made for a heavier flow. If you have to empty your cup more often than recommended, or heavy periods are affecting your life, talk to a doctor.
How much does a menstrual cup hold compared with tampons and pads?
A menstrual cup collects your flow instead of absorbing it. A 2023 review in Obstetrics & Gynecology puts cup volumes at 8 to 37 ml, and cites estimates that a fully saturated "super" pad may hold 5 ml and a night-time pad up to 15 ml.
| Product | How much it holds |
|---|---|
| Lunette cup, Size 2 | 30 ml |
| Lunette cup, Size 1 | 25 ml |
| Tampon | 6 to 18 g |
| "Super" pad | About 5 ml (estimate) |
| Night-time pad | Up to 15 ml (estimate) |
| Menstrual disc | 30 to 79 ml |
Pad and disc figures come from the 2023 review. The Lunette figures and the tampon range are Lunette's own. One ml of menstrual blood is comparable with a gram, Lunette notes. A Lunette cup holds about as much as three medium tampons.
Discs can hold more, but Lunette does not make one: see menstrual cup vs disc.
Which Lunette size is best for a heavy flow?
Size 2. It suits a heavier flow or a higher cervix, holds 30 ml to Size 1's 25 ml, and has a wider 46 mm rim and firmer silicone.
If you often need super tampons or change pads frequently on your heaviest days, lean towards Size 2. If your flow is heavy but your cervix sits low, the slimmer, softer Size 1 tends to sit more comfortably, so weigh capacity against comfort. The menstrual cup size guide walks you through it.
If your cup clearly doesn't work for you after a fair try of two to three cycles, Lunette refunds it or sends you the other size. Choose your Lunette menstrual cup, or see all Lunette menstrual cups in six colours.
How often should you empty a cup on heavy days?
More often than on lighter days. Lunette says that, depending on your flow, the cup may need to be emptied 2 to 4 times a day, and that with a heavy period you might want to empty it more often to prevent leakage. Cleveland Clinic gives the same advice for heavy flow days.
The Lunette cup can be used for up to 12 hours. Local restrictions may apply: legislation in France, Germany and Australia may limit use to 8 hours, and in France no overnight use is allowed.
That is a limit, not a target. Size 2 has measuring lines at 7.5 ml and 15 ml: check early, see how much you've collected and empty before the cup is full.
How to leak-proof your cup on heavy days
A review of 43 studies in The Lancet Public Health found leakage with cups similar to or lower than with disposable pads and tampons. Factors linked to leaks included heavy bleeding, needing a larger size, incorrect placement and a full cup. So check these four:
- Fold. Flatten the cup and fold it in half into a C-shape. If it doesn't open easily, try the punch-down or the 7-fold.
- Seal. Use a clean finger to check that the cup has fully opened: it should feel round and firm. Before you insert it, make sure the air holes near the rim are clear.
- Position. Guide the cup rim-first towards your lower back, not straight up. It belongs low in the vagina, below the cervix: leaks are more frequent when a cup is inserted too high.
- Back-up. Lunette Period Panties hold up to one menstrual cup or three tampons of blood. On heavier days, wear them with your cup.
Still leaking? Read why your menstrual cup might be leaking. The full steps are on how to use a menstrual cup and how to clean your menstrual cup.
Heavy flow overnight
Where local rules allow it, the Lunette cup can be worn overnight, within the 12 hours. Empty it right before bed and again when you wake up, with period panties as back-up.
ACOG lists needing to change pads or tampons during the night as a possible sign of heavy menstrual bleeding. If your cup regularly overflows at night, mention it to your doctor.
When does heavy bleeding need a doctor?
Heavy menstrual bleeding used to be defined as blood loss greater than 80 ml per cycle. The modern definition quoted in the 2023 review is "excessive menstrual blood loss which interferes with a woman's physical, social, emotional and/or material quality of life".
The NHS says you may have heavy periods if you:
- need to change your pad or tampon every 1 to 2 hours, or empty your menstrual cup more often than is recommended,
- need to use two types of period product together,
- have periods lasting more than 7 days,
- pass blood clots larger than about 2.5 cm,
- bleed through to your clothes or bedding.
The NHS advises seeing a GP if heavy periods are affecting your life, if you've had them for some time, if you have severe pain during your periods, or if you bleed between periods or after sex. ACOG adds that blood loss from heavy periods can lead to iron-deficiency anaemia.
The authors of the 2023 review recommend that doctors ask whether a cup fills or overflows, so note how often you empty and what the measuring lines show. For possible reasons behind a heavy flow, read heavy period causes.
Menstrual cups for heavy flow: frequently asked questions
Can you use a menstrual cup with a heavy flow?
Yes. The Lunette cup can be used throughout your cycle, from heavy to light flow days. On heavy days, empty it more often.
How often should I empty my cup on heavy days?
About 2 to 4 times a day depending on your flow, and more often with a heavy period.
Can I sleep with a menstrual cup on heavy nights?
The Lunette cup can be used for up to 12 hours, but local restrictions may apply: legislation in France, Germany and Australia may limit use to 8 hours, and in France no overnight use is allowed.
Is filling a menstrual cup quickly a sign of heavy menstrual bleeding?
It can be. The NHS lists emptying your menstrual cup more often than is recommended among the signs of heavy periods. If that is you, see a doctor.
Sources
- Liberty A, Samuelson Bannow B, Matteson K, Edelman A, Colwill A. Menstrual Technology Innovations and the Implications for Heavy Menstrual Bleeding. Obstetrics & Gynecology, 2023.
- 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.
- NHS. Heavy periods.
- American College of Obstetricians and Gynecologists. Heavy Menstrual Bleeding.
- Cleveland Clinic. Everything You Need To Know About Menstrual Cups.
This article is general information and is not medical advice.
