7 Factors in Picking the Right Menstrual Cup

Overnight menstrual protection without leaks

Pads and tam­pons con­sis­tent­ly failed to con­tain my heavy flow, and I used to resign to sleep­ing on a black tow­el every month.

Until I tried men­stru­al cups.

Menstrual cups have been an absolute GODSEND for me. They are the PEAK of con­ve­nience for the right users.

But the lack of infor­ma­tion in pick­ing the right men­stru­al cup for you often drove me bonkers.

Two cup sizes are usually marketed:

1. A small­er one for peo­ple who are under 25 and haven't giv­en birth
2. A big­ger one for peo­ple over 25 or have giv­en birth.

So to the layper­son, men­stru­al cup fit may sound like it's about hav­ing a tight vs. loose vagi­na. That's not the case, though.

Consider these other, potentially more relevant factors in choosing the right menstrual cup fit.

Table of contents

• Menstrual cup fit factors 
  • Cervix width
  • Resting vagi­na length
  • Menstrual flow
  • Changes through­out your period
  • Pelvic floor strength
  • Is your vagi­na eas­i­ly irritated?
• A start­ing point: sil­i­cone men­stru­al cup kits
• What's the best men­stru­al cup for yours truly?

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1. Cervix Width

Cervix shapes vary from per­son to per­son — there's a big range of "nor­mal!" Some are nar­row and pointy, while oth­ers are wider, rounder, more open, etc. And if your cervix is on the big­ger side, you'll want a men­stru­al cup that can seal over it to col­lect blood.

While it's true that your cervix gen­er­al­ly gets wider as you grow old­er or give birth, the cor­re­la­tion is not absolute. I'm over 25, and my cervix is still slen­der and tapered. Think of the stan­dard siz­ing guide­lines as more of a start­ing point.

What to look at

What's the men­stru­al cup's diam­e­ter and shape? And how does that com­pare to your cervix's shape and size?

I under­stand: the constantly-​shifting inter­nal anato­my is hard to mea­sure. So if you don't know how your cervix looks or can't reach to feel it, con­sid­er view­ing it with a (clean!) specu­lum, hand mir­ror, and flashlight.

2. Cervix Height/Resting Vagina Length

Oh gosh, I wish my younger self knew about cervix height's effect on men­stru­al cup fit. The gist is that the high­er your cervix is, the more you'd ben­e­fit from a long one.

It's not that you can't use a short men­stru­al cup with a high-​set cervix. It's just that the device may ride up and be hard­er to reach in and remove. The vagi­na is a finite space; things won't get "lost" in it. However, the strug­gle of pulling out an ill-​fitting men­stru­al cup is very real.

On the flip side, if you have a low-​set cervix or short vagi­na at rest, a long men­stru­al cup may not entire­ly fit inside. And hav­ing sil­i­cone pok­ing out of you isn't the most com­fort­able or con­ve­nient thing to deal with.

What to look at

When insert­ing your mid­dle or fore­fin­gers, how far can you go in before feel­ing your cervix? If you encounter it before the sec­ond knuck­le, a short­er men­stru­al cup may work bet­ter for you. If you can go past that (or all the way in), a longer one will be far eas­i­er to use!

Consider the cup's total length com­pared to that, if you're going to use the stem for removal. You may choose to trim it for com­fort, though.

3. Menstrual Flow

If you have a heavy flow, a larg­er cup means you'll have to emp­ty it (or worse, deal with leaks) less often. If you have a light flow, a small cup might ful­fill your needs just fine, while being more comfortable.

Ah, yes! Another rea­son I wish I said, "Fuck it" to the men­stru­al cup siz­ing guide­lines before. I had a heavy flow long before I was 25.

What to look at

How often do you change your pads or tam­pons? How quick­ly do they fill up?

4. Changes Throughout Your Period

The pre­vi­ous three fac­tors aren't nec­es­sar­i­ly sta­t­ic through­out your peri­od. You may find that your cervix gets high­er or flow gets dra­mat­i­cal­ly lighter, for example.

Some men­stru­al cup users pre­fer to have two sizes that they wear on dif­fer­ent days. The choice is all about you and your body.

5. Pelvic Floor Strength

Menstrual cups vary in not just shape and size, but also firm­ness. Stiffer ones form a tighter seal. I've seen advice that the soft­er ones are bet­ter for those who haven't giv­en birth, and vice versa.

On the con­trary, I've done vagi­nal weightlift­ing but found that firm men­stru­al cup rings work bet­ter for me. It's like I can eas­i­ly break the seal of a soft­er one when clench­ing or bear­ing down.

Fold a men­stru­al cup before insert­ing it. It will spring open and form a seal.

Further reading

• Guide to Kegel Progression & Vaginal Weightlifting
• Why a tight vagi­na isn't the same thing as a strong one

6. Is Your Vagina Easily Irritated?

I men­tioned before that some users might find a small­er or squishi­er men­stru­al cup more com­fort­able — it places less pres­sure on the wearer's walls and blad­der. If a small cup still col­lects blood well enough and works for you, have at it.

7. Impulsive Period Sex

I know: hav­ing sex in a tent while wear­ing a men­stru­al cup is odd­ly spe­cif­ic. My boyfriend and I were horny and tried it — and we both enjoyed the experience.

I was wear­ing a short, round­ed one with a min­i­mal retrieval stem (more like a nub) at the time. It's a pain in the ass for me to take out, and it's not the best for day wear… but it left my boyfriend's cock plen­ty of room to thrust!

The tiny stem was pushed a bit to the side, not pok­ing him at all. My cervix and A‑spot still felt plen­ty of sen­sa­tion to reach orgasm via deep pen­e­tra­tion.

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Summary of How to Choose a Menstrual Cup

I know that's a lot of infor­ma­tion. Let's dis­till it, so you don't get overwhelmed.

Shape and sizing tips

• Get a cup that fits your cervix width and rest­ing vagi­nal length.
• An immense flow means a big­ger cup is more convenient.
• Soft men­stru­al cups are more com­fort­able, but firm ones main­tain the seal better.
• Don't be afraid to use dif­fer­ent sizes on dif­fer­ent days.

Yes, intercourse and cervical orgasms are still possible while wearing a menstrual cup.

• I wouldn't rec­om­mend the Instead Softcup for that, despite their marketing.
• Get one that takes up less space in the vagi­nal canal.
• I know nobody asked, but it's good to know.

Overall, say "Fuck it" to absolute rules about menstrual cup fit. Listen to your body.

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A Starting Point: Menstrual Cup Sampler Kits

Kits you may see in sex shops include:

• Fun Factory's Fun Cups
• Intimina men­stru­al cups at Spectrum Boutique
  • Not a fan of the Ziggy
  • I'd stick with Size B for greater capacity

And of course, you can find the ubiq­ui­tous Diva Cup in drug­stores and some health food stores.

There's a boun­ti­ful vari­ety out there, so this list isn't at all com­pre­hen­sive; shop around to see what works for you!

Here's a quick summary of the menstrual cup measurements

	Capacity	Diameter	Length	Firmness
Fun Factory Fun Cup Size B	30 mL 🤩	1.7"	2.29"	Firm but flexible rim with thin cup
Fun Factory Fun Cup Size A	20 mL	1.56"	2.1"	Firm but flexible rim. Cup isn't as bendy as with Size B.

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What Do I Think Is the Best Menstrual Cup?

Of the four cups above, Fun Factory's Fun Cup Size B was the best fit for me.

Here's why I love the large Fun Cups so much:

• Collects sub­stan­tial­ly more blood than the others
• The cup's tapered shape doesn't ride up as easily.
• I rarely actu­al­ly use the retrieval stems anyway.
• Firm rim main­tains the seal
• The thin cup is oth­er­wise super comfy

My pref­er­ences don't mean that the Fun Factory Fun Cups will be the best men­stru­al cup fit for you. Not every­one likes the angling, for exam­ple. However, they're a fan­tas­tic option to con­sid­er for some­one with a long vagi­na and heavy flow, like me.

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Wrapping It Up

The most impor­tant rule to remem­ber is that there are no hard-​and-​fast rules. Just as sex toy pref­er­ences vary, so do opin­ions on the best men­stru­al cups!

Ultimately though, as long as my cup works, I'd choose that over a tra­di­tion­al tam­pon or pad most days. FUCK YEAH, clean sheets, min­i­mal main­te­nance, and danc­ing with no wor­ries about my period.

FURTHER READING: Find more of my favorite sex­u­al well­ness and body care prod­ucts!

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Thank you to Betty's Toy Box for spon­sor­ing this post. <3

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