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What is the diaphragm?

  • The diaphragm is a dome made of silicone that you fill with a spermicidal or barrier gel and put inside your vagina* to fit over your cervix. Spermicide is a chemical that kills sperm when it comes in contact with them. Barrier gel traps sperm and makes it difficult for them to swim.
  • Some types of diaphragms need to be fitted to the size of your cervix, and there is one variety, the Caya brand diaphragm, that fits most people without a fitting.

How does the diaphragm prevent pregnancy?

  • In order to get pregnant, sperm must enter the vagina, swim up into the uterus and fertilize an egg that has been released from your ovaries during ovulation. A diaphragm filled with gel covers the cervix (the entrance to the uterus), preventing sperm from getting inside and reaching an egg.
  • The spermicidal gel in the diaphragm kills sperm, or the barrier gel traps them. Diaphragms are unlikely to be effective without a spermicidal or barrier gel.

How effective is the diaphragm?

  • The fitted diaphragm with spermicidal or barrier gel is 96% effective. This means that if 100 people used the diaphragm correctly for one year, only 4 people would get pregnant.
  • The non-fitted diaphragm with spermicidal or barrier gel is 92% effective. This means that if 100 people used the diaphragm correctly for one year, only 8 people would get pregnant.
  • Because both kinds of diaphragm may be used incorrectly, they are closer to 75-80% effective with typical use.

How do you use the diaphragm?

  • You may want to practice finding your cervix before you put the diaphragm in. The cervix is located at the top of your vagina and feels kind of like the tip of your nose.
  • Before you insert the diaphragm, hold it up to the light to examine it for any cracks or holes or fill it up with water to see if there are any leaks. If you discover any leaks, throw it away and use another form of birth control until you can get a new diaphragm.
  • Add about one tablespoon of spermicidal or barrier gel to the hollow part of the diaphragm and along the rim.
  • Get into a comfortable position to insert the diaphragm. You may want to squat, put a foot up on a chair, or lie on your back.
  • With the hollow side of the spermicidal or barrier gel-filled dome facing up, fold 2 of the diaphragm’s sides together.
  • Insert the diaphragm deep into the vagina and push it past your pubic bone. Then use 1 or 2 fingers to move the diaphragm over your cervix. You should not feel the diaphragm once it has been inserted.
  • The diaphragm works immediately after you insert it.
  • For each additional act of vaginal sex, insert more spermicidal or barrier gel into the vagina (without removing the diaphragm) using the applicator that comes with the gel.
  • Leave the diaphragm in place for 6 hours after your last act of vaginal sex.
  • Do not leave the diaphragm in for more than 30 hours total.
  • You can insert the diaphragm before you plan to have sex. If it’s been over 6 hours since you’ve inserted it add more spermicidal or barrier gel into your vagina before having vaginal sex.
  • To remove the diaphragm, reach into your vagina with a finger and pull on the edge of the diaphragm.
  • Non-fitted diaphragms are designed to be easy to use, and there are videos online that demonstrate how to use them.
  • There is no risk of the diaphragm getting lost in your vagina. If you have trouble reaching it, try squatting to bring it closer to your vaginal opening or asking a partner to remove it.
  • If you have a physical disability, you may need a partner or support person to help you insert and remove the diaphragm.
  • A diaphragm will last for up to 2 years.
  • If you have a fitted diaphragm and have been pregnant or have a change in weight of 10 pounds (4 kg) or more since you were last fitted, you may need to be refitted for a new diaphragm.

How to start using the diaphragm

  • If you decide with your clinician that the fitted diaphragm is right for you, your clinician will refer you to a clinic that fits diaphragms.
  • At the fitting the clinician will do a pelvic exam, fit you for the proper size, teach you how to insert a diaphragm properly, and write you a prescription for a diaphragm.
  • Most non-fitted diaphragms come in a “one size fits all” model. If you decide the non-fitted diaphragm is right for you, the Caya diaphragm is available online (eg. or at some natural product stores for about $100.
  • Spermicidal gel is not sold in Canada. You will need to order it online or travel to the US to buy it. It costs approximately $15-18 per tube. One 90-120mL tube will last up to 11 uses.
  • Barrier gel (aka Contraceptive gel) is available online or at some natural product stores. It costs $23-$30 per tube. One 60mL tube will last up to 12 uses.

What are the side effects of the diaphragm?

  • Spermicidal gel used with the diaphragm can irritate your vagina or a partner‘s penis, causing burning or itching. Less commonly, barrier gel can cause irritation or allergic reactions.
  • The diaphragm can sometimes lead to vaginal infections like yeast or bacterial vaginosis (BV), especially if left in for too long.
  • It can increase some people’s risk of urinary tract infections (UTIs).
  • In rare cases the diaphragm can cause an allergic reaction and in extremely rare instances can cause Toxic Shock Syndrome (TSS).

Advantages of the diaphragm

  • You only have to use this method when you have sex.
  • You are protected for multiple acts of vaginal sex within 24 hours if you add new spermicidal or barrier gel for each act.
  • There are no hormonal side effects. People who can’t or do not want to take hormonal birth control can use this method.
  • It doesn’t affect your ability to get pregnant in the future.
  • Your partner(s) do(es)n’t have to be involved and shouldn’t feel the diaphragm during vaginal sex.
  • Depending on how often you use it, the diaphragm may be cheaper than other options like the pill.

Disadvantages of the diaphragm

  • You may have to order the spermicidal or barrier gel online or travel to the US to get it.
  • You have to do something before you have sex.
  • You have to remember to leave it in for 6 hours after the last act of vaginal sex before you can take it out. This may mean you have to wake up to remove the diaphragm or remove it at an inconvenient time.
  • You could forget to take it out.
  • You have to be comfortable touching the inside of your vagina.
  • You or your partner(s) could experience side effects.
  • The diaphragm does not protect you from sexually transmitted infections (STIs). Frequent use of spermicides can irritate the vagina, which can make getting some STIs more likely.
  • It can be difficult to find a clinician trained to fit a fitted diaphragm

For a downloadable resource on this topic, please visit Planned Parenthood Toronto Factsheet Database.

If you have questions about this topic, feel free to contact one of our peer educators. [Link]

*We know that these aren’t the words everyone uses for their bodies (eg. trans folks), and support you using the language that feels best for you.

Last Edited: May 2020