Contraceptive diaphragm / cap: everything you need to know
In this article
What's the lowdown?
Diaphragms or caps are silicon or latex contraceptives that are inserted inside the vagina to act as a barrier to sperm
They are 92–96% effective with correct use, though typical use tends to be less effective
Diaphragms are non-hormonal and are safe for people with latex allergies but do not protect against sexually transmitted infections
You have to be comfortable with insertion and removal of the diaphragm or cap and practice it
They are not recommended right after childbirth or for those with certain medical conditions
Diaphragms and caps are available through NHS services, usually at sexual health clinics
Diaphragms used to be a really popular contraceptive choice as a female controlled, discreet option. However, these days, they’re not seen as often and fewer clinicians either discuss them as an option, or know how to fit them. Here’s your guide if you’re fancying trying one out.
What is the contraceptive diaphragm or cap?
The contraceptive diaphragm or cap is a non-hormonal barrier method of contraception usually made of silicone. It works by physically blocking sperm from entering the opening of the womb (cervix), preventing pregnancy. This device is placed inside the vagina before sex and needs to be used with spermicide.
The diaphragm sits in the upper vagina covering the opening of the cervix, but the cap is a smaller device covering the cervix only which can be left in for longer.
How effective is the diaphragm?
When used consistently and correctly, the contraceptive diaphragm effectiveness is estimated to be between 92% and 96%1. This high effectiveness is achieved when the diaphragm is used with spermicide and correctly positioned in the vagina. However, typical use, which may involve occasional errors in application, can result in lower effectiveness (around 80%).
It’s important to note that the contraceptive diaphragm does not provide protection against sexually transmitted infections (STIs), including HIV, so it’s important to consider additional protection like condoms if STI prevention is needed.
How does the diaphragm contraceptive work?
The diaphragm contraceptive works as a barrier, preventing sperm from entering the cervix (the opening of the womb) and reaching the womb so it can’t fertilise an egg. When used with spermicide, the diaphragm also kills sperm, further reducing the risk of pregnancy.
The device covers the cervix, creating a physical block, and stays in place during intercourse. A properly fitted diaphragm is crucial for maximum effectiveness. If the diaphragm is too loose or too tight, it may not work as effectively, which is why a fitting with a healthcare provider is recommended.
How to use the diaphragm contraceptive
To use the diaphragm contraceptive, follow these steps:
- Apply Spermicide: Before insertion, apply 2cm of spermicide inside the diaphragm or fill a cap a third full of spermicide. You need to add spermicide again if it’s more than 3 hours before you have sex.
- Insert the Diaphragm: Insert the diaphragm so that it fits comfortably into the vagina. The rim of the diaphragm should sit behind the pubic bone for a secure fit.
- Check Placement: Ensure the diaphragm is covering the cervix completely. If it feels uncomfortable or misplaced, you may need to reposition it.
- After sex, the diaphragm should remain in place for at least 6 hours. Do not remove it immediately after sex, as this may reduce its effectiveness. If you have sex again, you should reapply spermicide and check the diaphragm for any signs of damage.
What to do when you remove the diaphragm
When you remove the contraceptive diaphragm, wash it gently with soap and water, and store it in a cool, dry place. Avoid using harsh chemicals or abrasive cleaners that could damage the material.
Diaphragms can stay inside for up to 24 hours after sex, a cap can stay in for up to 48 hours before removal.
Is the contraceptive diaphragm reusable?
Yes, the contraceptive diaphragm is reusable, making it a cost-effective option for long-term contraception. Typically, a diaphragm can last for 1-2 years2, but it should be checked regularly for any signs of wear or damage, such as holes or tears. It is also important to ensure the device fits properly, as changes in weight or after childbirth may require a new fitting.
Is the contraceptive diaphragm uncomfortable?
Discomfort with the diaphragm contraceptive varies between individuals. Some women report feeling the device during sex, while others find it more comfortable once properly fitted. According to studies, between 13% and 25% of couples have said they can feel the device or find it uncomfortable.
If you or your partner experience discomfort, it’s important to check the fit and ensure proper insertion. If problems persist, consult your healthcare provider for advice or to explore other contraceptive options.
Pros and cons of the contraceptive diaphragm
Pros of the diaphragm:
- Non-hormonal: The diaphragm is a non-hormonal method of contraception, making it ideal for those who cannot or prefer not to use hormonal contraception.
- Female-controlled: It gives women control over contraception, as the device can be inserted and removed independently.
- Latex allergy-friendly: Some diaphragms are made from silicone, making them suitable for those with a latex allergy.
Cons of the diaphragm:
- Effectiveness: The effectiveness of the diaphragm contraceptive is lower with typical use compared to long-acting methods like coils and implants. This means there’s a higher risk of pregnancy if not used correctly.
- No STI protection: The diaphragm does not protect against sexually transmitted infections (STIs), including HIV. It’s important to use condoms if you are concerned about STI transmission.
- Fitting: many brands of diaphragm have to be fitted by a healthcare professional to check the sizing and fit, this isn’t always easy as fewer clinicians have these skills given diaphragms are less popular these days.
- Spermicide: diaphragms and caps should be used with spermicides, but some people find these irritant or are even allergic to them
Diaphragm contraception side effects
The diaphragm contraceptive generally has few side effects, but some users may experience irritation, allergic reactions, or urinary tract infections (UTIs). There is also a small risk of toxic shock syndrome (TSS) if the device is left in for too long, so it is important to follow the recommended guidelines and remove the diaphragm after 6 hours.
Who is suitable for the diaphragm contraceptive?
Any woman can use the contraceptive diaphragm as long as she is comfortable with self-insertion and removal. It’s a good option for those who prefer non-hormonal contraception or have a latex allergy. However, if you are very concerned about pregnancy, you may want to consider more effective methods, such as a coil or implant.
If you’re not sure – check out our contraceptive recommender to find out your best fit!
Who is not suitable for the diaphragm contraceptive?
The contraceptive diaphragm is not recommended for women who have had difficulty with diaphragm use in the past or for those who have recently given birth (within 6 weeks). Additionally, women with certain medical conditions, such as pelvic organ prolapse, may need to avoid this method.
If you are living with HIV or have had toxic shock syndrome in the past, the diaphragm or cap are not recommended to use.
Can I use lubricant with a contraceptive diaphragm?
Yes, you can use lube with a diaphragm, however, it’s advisable to use water based or silicon based lube, and avoid oil based lube to make sure there is no damage to the diaphragm.
Where to get a contraceptive diaphragm?
You can access contraceptive diaphragms through contraceptive services available on the NHS. These devices are available at sexual health clinics, where trained staff can fit them and show you how to use them. You can find your local sexual health service and more information on the NHS3 website.
What are the different brands of diaphragm or cap?
In the UK there are 2 brands of diaphragm available: the Caya and the Singa.
The Caya diaphragm is made from silicone and can be bought online. It is available in one size which fits approximately 80% of women.
The Singa diaphragm is a traditional circular design, made from silicon and is available in more sizes, specifically for those women who don’t fit a Caya. It needs to be fitted by a trained healthcare professional and you should have a refit after pregnancy, delivery or if your weight fluctuates by 4-5kg.
The FemCap is the only cervical cap brand available. It is made from silicon and doesn’t need to be formally fitted. The size is chosen depending on previous pregnancies and deliveries. If you’re still unsure – check out the reviews on The Lowdown to see what other women like you think of their experience with the diaphragm or cap.
Dr Nirja Joshi
General Practitioner
Dr Nirja Joshi is a dedicated General Practitioner with a special interest in women’s health and wellbeing. Holding a Diploma from the Faculty of Sexual and Reproductive Health (DFSRH), she is a passionate advocate for empowering patients through accessible, compassionate care. Beyond the consulting room, Dr Nirja is the co-founder of The WorkWell Doctors, an initiative aimed at promoting wellbeing in the workplace. Her work in this area has been recognised with the Inspire Award (2022) from the Royal College of General Practitioners, celebrating her outstanding contribution to the field of wellbeing. In addition to her clinical role as a GP, Dr Nirja brings a creative flair to her professional life, with experience in medical copywriting and a background as a dance teacher—reflecting her belief in the importance of holistic wellbeing and the arts in health.
Our medical review process
This article has been medically reviewed for factual and up to date information by a Lowdown doctor.
