A diaphragm is a flexible cup made of soft silicone (or sometimes latex). You insert it into your vagina before sex to cover your cervix and block sperm.

  • frequency: before sex

  • effectiveness: 88%

  • STI protection? no

  • periods: no change

What you need to know about the diaphragm

Diaphragms are a barrier form of contraception. They fit inside the vagina and prevent pregnancy by stopping sperm reaching the womb and fallopian tubes. You need to use spermicide with them (a gel that kills sperm). And you need to leave it in for 6 hours after sex.

How does the diaphragm work?

Diaphragms traditionally came in different sizes and your first one needed to be fitted by a health professional. There's now a one-size type you can get from a pharmacy without fitting, but you may still want to get advice on using them correctly.

How to use the diaphragm

It can take time to use a diaphragm properly, adding spermicide and inserting it correctly. You can buy them from pharmacies and some online stores, but if you’re not confident using them it’s a good idea to make an appointment with a doctor or nurse.

Health benefits, risks and side effects of the diaphragm

Once you’re used to using your diaphragm it’s easy to use, even for unplanned sex. If you use and store it carefully you can use it for up to a year. It’s hormone-free contraception so doesn’t affect your periods or have any side effects. But it doesn’t protect against STIs.

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