Five myths about menstrual cups

There are so many myths about menstrual cups and menstruation. Does the blood flow back into the womb when the cup is full? Is it true that virgins can’t use period cups? We put all the facts on the table and gathered the most common myths and truths.

Separate the fact from the fiction

1. MYTH: When the cup is full, the blood flows back into the uterus.

TRUTH: Wrong! The blood flows into the vagina and thus into the cup through the tiny hole in the cervix. It is not possible for the blood to flow back into the womb, not even if you're upside down. The muscles of the uterus push the menstrual blood out actively from the uterus.

2. MYTH: You can't use a menstrual cup if you have endometriosis.

TRUTH: Wrong! It is completely safe to use a menstrual cup if you have endometriosis, just ask your doctor first! Read our article ‘What is endometriosis?

3. MYTH: Virgins cannot use menstrual cups.

TRUTH: Wrong! Even people with a uterus who have not had penetrative sex can use the cup. The vagina may occur ‘narrower’ with a virgin vagina, and the hymen may still be present, but these facts do not prevent the use of the cup. At most they'll bring light challenges the first few times of inserting the cup.

4. MYTH: You can go pee and poo while having a menstrual cup inserted.

TRUTH: True! With the cup inserted, you can easily go to the bathroom if you make sure it's not out of place, like during a bowel movement. Good hygiene is essential so that no foreign bacteria enter the vagina or cup. If you want to make sure you're comfortable and clean, remove the cup before going to the toilet and wash your hands (and down there) carefully before inserting the clean cup. You can empty the cup as often as you'd like!

5. MYTH: You don’t need to boil your menstrual cup after every cycle

TRUTH: Sort of. Your menstrual cup does not necessarily have to be boiled every cycle (although we highly recommend it). However, before you use your cup for the first time, make sure to boil it for 20 minutes. Read our article ‘How to clean’ for full instructions. After your first use, boiling it for 10 minutes is good enough. Keep an eye on your menstrual cup when you boil it, you wouldn't want it to forget about it and have it burn at the bottom of the pot! Whatever you do, do not use a hand sanitizer. You can buy cup wipes that are specifically designed for menstrual cups, with no colorants, oils or scents that could damage the silicone. And don’t forget good hand hygiene!

If you’ve still got a question, or want to read more about the things people are curious about, check out our article ‘Everything you’ve ever wanted to ask your OB/GYN’.

11 comments

It is recommended to use a small cup from my age group but I have heavy flow. Will the cup leak if it is full? For example if I sleep with my cup in on my heavy days will I wake up with blood leaking all over?

Drush August 24, 2020

Hi Anonymous! Blood will not flow back into the uterus once it has passed through the cervix. You can wear your cup while swimming and diving, it cannot get lost inside. :) Just be sure to use your pelvic muscles to push the cup lower when removing, that way you’ll be able to reach it easier. <3
-Team Lunette

Lunette Menstrual Mentor August 05, 2020

If I go upside down will the blood come back into me? Also I do diving and can I wear a tampon or cup while diving or will it get stuck up there from the impact and pressure.

Anonymous August 05, 2020

Hi, Mysti! There are a couple of reasons that can cause the cup to slide down. The most common ones are:
*the cup is not completely open and has not created a good seal

the cervix comes lower during periods and may be pushing the cup out
*your pelvic muscles cannot hold the cup in place

Don’t hesitate to contact us at info@lunette.com and we’re happy to troubleshoot further!

-Team Lunette

Lunette Mentrual Mentor July 10, 2020

what would cause a cup to fall out? I was asleep, woke up after 8 hours, I had very bad cramps, went to the restroom ( my urge to urinate was worse than to immediately remove the cup) I wiped and just as I was about to stand up, the cup fell out into the toilet. It was not hanging out, I didn’t feel it when I was wiping. What would make this happen?

Mysti July 10, 2020

Hi Lucky,

Thanks for your question! It’s possible for the cup to leak in any position, sleeping, sitting, or standing up. This can happen if the cup does not have a proper seal. If you’re experiencing leaking don’t hesitate to reach out at info@lunette.com so we can help troubleshoot the issues you’re having! :)

Best,
Team Lunette

Lunette Menstrual Mentor December 15, 2019

When I lay flat on my back, side, or stomach to sleep while wearing the cup, is it possible for blood to seep out? Also if it is not possible, does the blood stay in the cup?

Lucky December 15, 2019

Hi Anonymous,

If neither one of you is suffering from any type of vaginal bacterial or yeast infection, then 20 minutes of boiling together should sterilize both cups sufficiently to be safe to use. Even though medical grade silicone is a very unfavorable platform for bacteria and yeast to live, it is still possible they will live after boiling- therefore, if either one of you is treating an infection and there is a change this bacteria or yeast was on a cup when they were boiled, it is possible that bacteria could have been transferred.

Hope this helps!

Best,
Team Lunette

Lunette Menstrual Mentor December 01, 2019

Hi there,

I boiled my friend’s and my own lunette together, in the same pot. It occurred to me later that germs could probably be shared this way. Is this something I need to be concerned about?

Thank you!

Anonymous December 01, 2019

Hey Michelle,

Great question!

Inserting your menstrual cup in anticipation of your period will not delay your period, but will leave you feeling fresh AF. <3

Just remember that you always need to remove and thoroughly clean your cup within that 12 hour timeframe, even if you’re experiencing a very light flow.

For any other questions, please don’t hesitate to reach out to us at info@lunette.com.

Lunette Menstrual Mentor June 17, 2019

If you insert cup before your period (in anticipation) will it delay your period?

Michelle June 17, 2019

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