Do you mean a diaphragm?

A patient of mine wanted to explore some non-hormonal contraceptive options. We were discussing condoms, the Copper IUD, spermicide, lactic acid suppository (Phexxi), and then she said:

“Well, I do have that thing from the 1940s that you shove inside your vagina and it blocks sperm”. 

I answered: “Ummmm …. Do you mean a diaphragm?”

Let’s discuss. 

The diaphragm and its little sister, the cervical cap:

It is true that both are placed inside the vagina to block sperm from getting to the cervix and that blocks sperm from traveling up to the uterus and fallopian tubes. Both are used in conjunction with spermicide to maximize their efficacy. 

What else is the same? 

  • They both physically cover the cervix (but the cervical cap covers just the cervix, and the diaphragm covers the upper part of the vagina which includes the cervix)
  • Need to leave them in for 6 hours AFTER sex. Taking them out too soon makes them less effective
  • Can place them hours before sex so you don’t have to excuse yourself in the heat of the moment
  • May need a little practice to get them in the proper position
  • Need to be comfortable placing them in order to use them
  • You and your partner are not likely to feel them or notice them
  • If you’re having sex more than once, need to check that it’s in the proper position and reapply spermicide each time
  • Shouldn’t use if significant pelvic floor relaxation, like prolapse
  • Neither prevent against STIs (although this is being studied and the diaphragm may actually provide a bit of protection)
  • Both are made of silicone
  • Both require prescription

What are some differences?

  • The cervical cap covers just the cervix. The diaphragm covers the upper part of the vagina which includes the cervix. 
  • Cervical caps are better if you’ve never given birth. That’s because the cervix changes and becomes larger after childbirth (no, it doesn’t matter if baby was born via vaginal or cesarean birth). Diaphragms can be used for people who have and haven’t given birth.

In general, between these 2 options, my STRONG PREFERENCE IS FOR THE DIAPHRAGM. It’s easier to learn to use. It’s easier to get. It’s more effective because it’s easier to use and easier to get. People prefer the insertion over the cervical cap too. Both aren’t popular contraceptive options (less than 2% of the population uses the diaphragm, even less for the cervical cap), but the diaphragm is more popular – likely for all these reasons! 

Photo: Jen Theodore

Let me give a few more diaphragm details:


It can be placed hours before sex (no specific time frame, but less than 6 is generally recommended). 

It can be removed anywhere between 6 to 24 hours after sex. 

You can’t remove it right away or it won’t be effective (if there are active sperm inside the vagina, they can migrate up if you move it too soon!


Does anyone else remember when Samantha had to take out Carrie’s diaphragm in Sex in the City and that’s how all the girls found out Carrie was sleeping with Big again? Just me? 

Well, it is true that sometimes diaphragms can be challenging to get out. Moving your body in different positions (one leg up, squatting, lying on bed in happy baby pose) may help. And if it’s truly stuck, visit your OBGYN – we’ve removed far weirder things than this. 


Do you need a “diaphragm fitting”? Maybe.

Before prescribing a diaphragm, your doctor will likely do a pelvic exam to make sure you would be a good candidate based on anatomy (such as no significant prolapse).  We also assess your comfort level on insertion (you basically tell us, after we describe how best to insert and use a diaphragm). 

If you’re getting the Caya, this is enough. Caya is a “one size fits most” diaphragm. It’s thought that it will fit 80% of the population. This is the reason a pelvic exam can be helpful – a health care practitioner can help assess if you’re in this 80%. A prescription is given and almost everyone can then place it successfully on their own. Studies show that almost 95% of people can place it properly. 

If you’re getting the other available brand, the Milex, a bit more is needed. 

Milex has different sizes and the right size needs to be prescribed. This is where the “fitting” comes in. It can be done one of two ways:

  • Your doctor’s office may have a diaphragm fitting kit. This is a sterilized sample diaphragm kit that is kept in the office. Different sizes are tried on (or should we say … tried in) to find out which size is ideal for you.  I’m not going to lie – the old school OBGYN offices may have these, but the only time I’ve ever seen one, it was so old that it was brittle.  I’ve never requested one in any office I’ve ever had. 
  • So most people do the second way: the size of diaphragm that will likely fit is assessed in the office. That size is prescribed, the patient picks it up and brings it to the office, and we practice insertion and removal and check that it actually does fit. I have done that exactly twice in my entire 15-year career as an OBGYN. It’s not hard, but certainly a hassle.  


I know, I know. Most people choose other forms of contraception because they don’t like the idea of spermicide. But it’s recommended to make the diaphragm more effective in preventing pregnancy. There are only a few studies that compared diaphragm use with and without spermicide. That data showed a typical efficacy rate of 80% with spermicide and 70% without. So … yeah … use the spermicide.

Now, remember Phexxi – the vaginal pH “regulator”? I think of it a spermicide without the chemicals and irritation. Could this be used instead of spermicide? Probably. In fact, the Caya website sells a “Caya diaphragm gel” that is recommended for use instead of spermicide. And that gel’s primary ingredient is lactic acid – the same as Phexxi! There’s not a lot of data, but I say go for it! 

AND THE LAST THING ….  Was my patient right? Are they from the 1940s? 

Guttmacher Institute to the rescue with all contraceptive facts again! 

The vaginal diaphragm was invented in 1842 and that makes it one of the oldest contraceptive methods. So yeah, it is from the 40s … the 1840s! In the 1930s it was the most frequently prescribed contraception. But nowadays, it’s reported that only about 2% of females use it for contraception.  

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