PrEP for Women: Which Option, How Long It Takes, Contraception, Pregnancy and Breastfeeding

A lot of PrEP information is written with gay and bisexual men in mind. But PrEP is for anyone without HIV who may be exposed through sex or injecting drugs, and that includes women¹. There are a few differences that matter for women, and anyone at risk through receptive vaginal sex: which pills are approved, how long protection takes, and how PrEP fits with contraception, pregnancy and breastfeeding.

Which PrEP options suit women

• Truvada and its generic versions (emtricitabine with tenofovir disoproxil fumarate): a daily pill approved for all people at risk through sex or injecting drugs². This is the usual PrEP pill for women.
• Descovy (emtricitabine with tenofovir alafenamide): not for women at risk through receptive vaginal sex². Its label explains that its effectiveness for people at risk through receptive vaginal sex has not been evaluated⁶.
• Injections: Apretude (every two months) and Yeztugo (twice a year) are approved for adults and adolescents at risk of HIV through sex, including women². Our guide to the PrEP shot compares them with pills.

Daily or event-based PrEP for vaginal sex?

US guidance is daily PrEP. The CDC says the on-demand “2-1-1” schedule has evidence for gay and bisexual men having anal sex, but there is not enough evidence for vaginal sex¹.

The 2025 UK guidelines go further. They allow anyone at risk through receptive vaginal sex to start with a double dose (two pills) 2 to 24 hours before sex, and to keep taking one pill a day until 7 days after the last sex, a pattern called 2:7. They stress that fewer than seven daily doses after the start is likely to give less protection³. Daily PrEP remains an option for everyone.

How long until PrEP works for vaginal sex

The CDC says that for receptive vaginal sex, daily PrEP pills reach maximum protection after about 21 days, longer than the 7 days quoted for receptive anal sex¹. Under the UK guideline, protection is built by the double-dose start followed by daily pills, continued for 7 days after the last sex³. Follow the schedule your prescriber gives you, and use condoms in the meantime if you are unsure. Our guide to starting, missing and stopping PrEP covers the details.

PrEP and contraception

The CDC says there are no known interactions between PrEP and hormonal birth control, including the pill, patch, ring, injection, implant or hormonal IUD, and that it is safe to use both at the same time¹. The UK guideline adds that in the Partners PrEP study, PrEP did not affect how well the pill, the contraceptive injection or implants prevented pregnancy³.

Remember that it works the other way too: PrEP does not prevent pregnancy, and it does not protect against other sexually transmitted infections¹. Our guide to the combined pill covers contraception.

Trying for a baby, pregnancy and breastfeeding

The CDC says PrEP can help prevent HIV while trying to conceive, during pregnancy and while breastfeeding, which also protects the baby from HIV exposure¹. The UK guideline summarises the evidence³:

• Studies suggest PrEP is safe in pregnancy, and the benefits of preventing HIV in pregnancy greatly outweigh any possible risks to mother or baby.
• PrEP appears safe for babies during breastfeeding; only very small amounts of the medicines pass into breast milk.
• There is no evidence that PrEP affects fertility in women or men.

If your partner has HIV, their treatment matters too. People with HIV who keep an undetectable viral load do not pass HIV on through sex⁴. The UK guideline describes PrEP as one option for couples trying to conceive when the partner with HIV is not yet on effective treatment³. Our guide to PrEP when your partner is undetectable explains the choices for mixed-status couples.

If you become pregnant while on PrEP, do not just stop. Talk to your clinic, which can review your risk and how you take it.

Side effects, bones and kidneys

Women report the same side effects as anyone else on PrEP: nausea, diarrhoea, headache, tiredness or stomach pain, usually in the first few weeks¹. Kidney tests are part of PrEP for everyone. Bone density can fall slightly on Truvada-type PrEP, and the drop appears a little larger in people aged 25 or under, who are still building bone. It has been shown to recover after stopping³. Our guide to PrEP side effects covers this in more detail.

Tests and getting a prescription

• Before you start: an HIV test, a hepatitis B test (with vaccination if you are not immune), a kidney test and STI screening³.
• While on PrEP: an HIV test every 3 to 6 months, kidney checks on a set schedule, and STI screening every 3 months if you have new or multiple partners³.
• Who can prescribe: in the US, any healthcare provider who can write prescriptions, including pharmacists in some states². In the UK, PrEP is free from NHS sexual health clinics⁵.

Generic daily PrEP, such as Tenvir-EM (the same ingredients as Truvada), is covered on our generic Truvada page and in our PrEP guide, including prescription and import rules.

Frequently asked questions

Can women take PrEP?

Yes. Truvada and its generic versions, and the injections Apretude and Yeztugo, are approved for women at risk of HIV through sex. Descovy is not approved for women at risk through receptive vaginal sex.

Does PrEP affect birth control?

No. The CDC says there are no known interactions between PrEP and hormonal birth control such as the pill, patch, ring, injection, implant or hormonal IUD. PrEP itself does not prevent pregnancy.

Is PrEP safe in pregnancy?

Studies suggest it is, and US and UK guidance say PrEP can be used while trying to conceive, during pregnancy and while breastfeeding. Discuss your plans with your clinic.

How long before PrEP works for women?

The CDC says about 21 days of daily pills for receptive vaginal sex. The 2025 UK guideline allows a double-dose start, then daily pills continued until 7 days after the last sex.

Can women take Descovy for PrEP?

Descovy is not approved for people at risk through receptive vaginal sex, because its effectiveness in that group has not been evaluated. Truvada or a generic version is used instead.

Can I take PrEP while breastfeeding?

Yes. The UK guideline says PrEP appears safe for babies during breastfeeding, with only very small amounts passing into breast milk, and the CDC lists breastfeeding as a time when PrEP can help.

Sources & references

1. Centers for Disease Control and Prevention. Preventing HIV with PrEP.
2. HIV.gov. Pre-Exposure Prophylaxis (PrEP). Updated 9 October 2026.
3. British Association for Sexual Health and HIV and British HIV Association. BASHH/BHIVA guidelines on the use of HIV pre-exposure prophylaxis (PrEP) 2025.
4. HIV.gov. HIV Treatment as Prevention. Updated 28 August 2026.
5. NHS. HIV and AIDS: prevention. Last reviewed 9 July 2025.
6. US National Library of Medicine, DailyMed. Descovy prescribing information.

Related reading

• PrEP with alcohol, drugs and hormones
• HIV, pregnancy and breastfeeding
• Truvada vs Descovy
• PrEP: daily vs on-demand
• PrEP vs PEP
• All HIV and PrEP medicines

This content is for informational purposes only and is not medical advice. If you are pregnant, trying to conceive or breastfeeding, plan your PrEP with your clinic. Used as prescribed by a licensed medical professional.