Contraceptive diaphragms and caps – the lowdown

7th December, 2022 • 11 min read

You might not have thought about using a contraceptive diaphragm or cervical cap – they’re the sort of birth control your mom used, right? But they’re making a comeback. Find out how they work, how you get them fitted, and the pros and cons – to see if they might be the right contraceptive for you.

What is a diaphragm?

Diaphragms and caps are both types of barrier

contraception
.

They fit inside your vagina and stop sperm getting through your cervix and into your womb. They need to be used with spermicide – a chemical that kills sperm.

Diaphragms

A diaphragm is a reusable dome-shaped cup with a flexible rim, which you put inside your vagina before having sex.

They’re made in different sizes and are usually fitted by a doctor or nurse, to make sure they’re comfortable for you. You may need to have a new one fitted after childbirth, or if your weight changes.

There are 3 types of latex diaphragm:

  1. Latex arching spring diaphragm – the most common type, this is easy to insert, has a firm rim and can be helpful if you have weak vaginal muscles.
  2. Latex coil spring diaphragm – this has a softer rim, is flexible and works well if you have average vaginal muscle strength.
  3. Latex flat spring diaphragm – similar to the coil spring, but with a thinner rim, this works well if you have strong vaginal muscles.

There are 2 types of silicone diaphragm:

  1. Wide seal rim diaphragm – this comes in both arching and coil spring shapes. Because it’s silicone, it’s suitable if you have a latex allergy or sensitivity.
  2. Single-size diaphragm (single-size contraceptive barrier device, or SILCS diaphragm) – this newer, ‘one size fits most’ type is becoming increasingly popular. It’s softer and more durable than a latex diaphragm, and appears to have a lower risk of
    urinary tract infections (UTIs)
    than older types (a downside of diaphragm use for some women).

Cervical caps

A cap is similar to a diaphragm, but it’s smaller, and shaped like a thimble or a sailor’s hat. Made of silicone, it also comes in different sizes to make sure it fits correctly.

How effective are diaphragms and caps?

With ‘typical’ use – how they’re usually used in real life – diaphragms and caps are between 71% and 88% effective. This means that in a year, between 12 and 29 out of 100 women who use them get pregnant.
However, if you use them perfectly every time you have sex, they can be 92% to 96% effective. Between 4 and 8 women in every 100 using them in this way would get pregnant every year.

Taking care of your diaphragm or cap helps it stay effective

After you’ve used your diaphragm or cap, wash it thoroughly with mild unperfumed soap and warm water, before rinsing it and leaving it to dry. Once dry, put it in its container and keep it in a cool, dry place.

Remember these points to help keep it in good condition:

  • never boil your diaphragm or cap
  • don’t use disinfectant, detergent, oil-based products or talcum powder when cleaning it
  • use only water or silicone-based
    lubricants
    , if needed – avoid oil-based lubricants
  • check for signs of damage before use – if it’s damaged, arrange to get a replacement and use another form of contraception in the meantime. But don’t worry if it becomes a little discolored over time – this is normal, and doesn’t make it less effective

Diaphragm and cervical cap pros and cons

Advantages

  • no hormones – some people prefer non-hormonal methods of contraception
  • convenient – you can keep a diaphragm or cap in your pocket or purse, and it’ll be effective as soon as you want to use it
  • reusable – they can be used repeatedly for up to 2 years if they’re looked after
  • doesn’t interrupt sex – you can insert it before you have sex
  • doesn’t change how sex feels – you and your partner shouldn’t feel a diaphragm or cap during sex

Disadvantages

  • doesn’t protect against
    sexually transmitted infections (STIs)
    – if you want to prevent STIs, you’ll need to use
    condoms
    as well
  • you need to get a new diaphragm or cap every 2 years or so
  • you might need to be fitted for a new diaphragm if your weight changes or you have a baby,
    miscarriage
    or
    abortion
    (talk to your doctor or nurse for advice)
  • you have to apply extra spermicide if you have sex more than once
  • you can’t use them during your
    period
    – as they can lead to an increased risk of
    toxic shock syndrome (TSS)
    – or when you have a vaginal infection

Who can’t use diaphragms and caps?

Most women can use a diaphragm or cap. But they might not be suitable if you:

  • have an unusually shaped or positioned cervix
  • can’t reach your cervix
  • aren’t comfortable touching your vagina
  • have vaginal muscles that aren’t strong enough to hold it in place (sometimes as a result of giving birth)
  • have an
    allergy
    or sensitivity to latex, or the chemicals in spermicide
  • have a high risk of getting an STI – if you have multiple sexual partners, for example
  • get recurring UTIs – spermicide can affect the balance of bacteria in your vagina and make it more likely to get infections
  • have had TSS in the past

Where can I get a diaphragm or cap?

  • in the US, you can buy them at a pharmacy, drugstore or health center with a prescription from your doctor or nurse, and your healthcare provider will show you how to fit them. (You don’t need a prescription to buy spermicide gels and creams)
  • you can usually get them for free, or a reduced price, if you have health insurance. If you don't have insurance, you may qualify for Medicaid or other state programs that can help, depending on your income and legal status
  • in the UK, you can get them for free from NHS sexual health clinics, contraception clinics, some young people’s services and most GP surgeries

How to insert a diaphragm

It’s usually recommended that you see a doctor or nurse to teach you how to fit a diaphragm.

You can put it in up to 3 hours before you have sex. If you put it in earlier, you’ll need to add extra spermicide after 3 hours – and you should never leave it in for more than 48 hours.

To insert your diaphragm:

  • wash your hands with soap and water
  • apply spermicide inside the dome and around the rim of the diaphragm
  • find a comfortable position, such as you would use when inserting a
    tampon
    or
    menstrual cup
  • with one hand, part your vaginal lips. In your other hand, hold the diaphragm, with the dome part pointing toward your palm
  • pinch the sides of the diaphragm together so that it’s small enough to fit inside your vagina, then gently slide it inside, pushing it as far back as it will go
  • check that your cervix is covered by feeling inside – it’s a small lump at the top of your vagina. (You can practice finding your cervix by inserting a clean finger into your vagina until you can’t go any further.) If your cervix isn’t covered, remove the diaphragm by hooking your finger under the rim or loop and pulling down, then inserting it again. It should fit comfortably without causing you any irritation
  • apply more spermicide inside your vagina after you’ve inserted the diaphragm

After having sex, you should leave your diaphragm in place for at least 6 hours (but less than 48 hours) – taking it out too early can prevent the spermicide from killing all the sperm.

Douching can also rinse out spermicide, so avoid this within 6 hours of having sex.

How does a diaphragm feel?

If you’ve inserted your diaphragm correctly, you shouldn’t be able to feel it inside you.

It shouldn’t cause any discomfort or irritation, and you and your partner shouldn’t be able to feel it during sex.

Signs a diaphragm or cap isn’t in place properly

Once you’ve learned how to insert your cap or diaphragm, you’ll know how it feels and how comfortable it is. If it isn’t in the right place, it’s likely that you’ll feel some discomfort or irritation.

How to insert a cap

Like a diaphragm, a cap can be inserted up to 3 hours before sex – if you want to put it in earlier, you’ll need to apply extra spermicide after 3 hours.

To insert your cap:

  • wash your hands with soap and water
  • put a small amount of spermicide in the cap and spread a thin layer on the flat part of the rim, as well as in the groove between the brim and the dome
  • get into a comfortable position and separate your vaginal lips with one hand
  • squeeze the rim of the cap with your other hand, put it into your vagina so the side with the dome faces down, and push it deep inside
  • once it’s in place, make sure your cervix is covered. If it isn’t, pull the cap out by hooking your finger under the rim and pulling down, then try again

After having sex, leave your cap in place for at least 6 hours, but not more than 48 hours. If you have sex again you can leave your cap in, but put a new dose of spermicide into your vagina.

How your doctor can help

Because diaphragms and caps come in different sizes, they should always be first fitted by a specially trained nurse or doctor. They’ll also teach you how to insert it yourself.

At your fitting:

  • your doctor or nurse will talk to you about your sexual history, health, and what type of diaphragm or cap might work for you
  • if a diaphragm is a good option for you, they’ll do a gentle vaginal examination to see what size you’ll need
  • they’ll then show you how to apply spermicide and fit it so that it’s in the right place
  • don’t worry if you’re nervous or embarrassed – they’ll be used to this, and will talk things over to help you relax

Once you have a diaphragm or cap, you may need to see your doctor or nurse for a refitting if you:

  • have had it for more than a year
  • gain or lose more than 10lbs
  • have a baby, miscarriage or abortion

When to see a doctor urgently

You should speak to your healthcare provider right away if you notice:

  • symptoms of TSS
    – such as a high fever, weakness, vomiting, diarrhea or a rash that resembles sunburn
  • symptoms of a UTI
    – such as painful or frequent urination and vaginal discharge
  • blood in your diaphragm when you’re not on your period
  • vaginal pain or itching

Your health questions answered

Can I use a condom and a diaphragm at the same time?

“You can,” says

Dr Roger Henderson
, Healthily clinical writer. “Although a diaphragm is an effective method of contraception when used perfectly every time, using it with another method – such as condoms – can further reduce your risk of pregnancy. Condoms also have the added benefit of protecting against STIs.”

Can a diaphragm or cap get dislodged during sex?

“If you have very vigorous sex, with lots of hard thrusting and deep penetration, it’s possible for a diaphragm or cap to become dislodged or move out of place,” says Dr Roger. “If you think this is a possibility, you might want to use a condom as well.”

Can I have a bath when a diaphragm or cap is in place?

“Water can cause a diaphragm or cap to move, or wash away the spermicide,” says Dr Roger. “So have a shower instead of a bath when you’ve got your diaphragm or cap in.”

Important: Our website provides useful information but is not a substitute for medical advice. You should always seek the advice of your doctor when making decisions about your health.