References UK clinical guidance from the NHS, the British HIV Association (BHIVA), and the British Association for Sexual Health and HIV (BASHH). Last updated: April 2026.
With effective antiretroviral treatment, the risk of a mother passing HIV to her baby is less than 1% in the UK. Without treatment, the risk is 15-45%. This dramatic reduction is one of the greatest successes of modern HIV medicine.
If you’re pregnant and living with HIV, or planning a pregnancy, the most important thing is to be on effective treatment with an undetectable viral load. Here’s how mother-to-child transmission is prevented in the UK.
When Can HIV Be Transmitted to a Baby?
| Stage | Risk Without Treatment | Risk With Treatment |
|---|---|---|
| During pregnancy | 5-10% | <0.5% |
| During labour and delivery | 10-20% | <0.5% |
| Through breastfeeding | 5-20% (over 2 years) | Very low (with treatment + guidance) |
How Is Transmission Prevented?
All pregnant women with HIV should be on ART, ideally before conception. If diagnosed during pregnancy, treatment should start as soon as possible. The goal is an undetectable viral load by 36 weeks of pregnancy at the latest.
Mode of delivery
If your viral load is undetectable by 36 weeks, vaginal delivery is safe and recommended. If viral load is above 400 copies/ml near delivery, a planned caesarean section at 38 weeks is recommended to reduce transmission risk.
Infant treatment
All babies born to mothers with HIV receive antiretroviral medication (usually zidovudine syrup) for 2-4 weeks after birth as additional prevention.
Feeding
In the UK, formula feeding has traditionally been recommended to eliminate breastfeeding transmission risk entirely. However, BHIVA updated its guidance in 2024: women on effective ART with a sustained undetectable viral load may choose to breastfeed with appropriate support and monitoring. This is a shared decision with the HIV team.
HIV Testing in Pregnancy
In the UK, all pregnant women are offered an HIV test as part of routine antenatal screening. This is a simple blood test done at the booking appointment. Early detection allows treatment to start promptly, protecting both mother and baby.
Read more: What is HIV? | Getting pregnant with HIV | Feeding your baby with HIV
Frequently Asked Questions
Can I have a natural birth if I have HIV?
Yes, if your viral load is undetectable by 36 weeks of pregnancy. Vaginal delivery is safe and recommended in this situation. Your HIV team and obstetrician will plan your delivery together.
Will my baby definitely be HIV-negative?
With proper treatment (maternal ART + infant prophylaxis), the chance of transmission is less than 1%. Your baby will be tested for HIV at birth, 6 weeks, 12 weeks, and 18 months to confirm their status.
Can I breastfeed with HIV?
Updated BHIVA guidelines (2024) allow breastfeeding for women on effective ART with a sustained undetectable viral load, with appropriate support and monitoring. This is a personal decision made with your HIV team. Formula feeding remains a safe alternative that eliminates any breastfeeding transmission risk.
Related reading
- Can You Catch an STI From a Toilet Seat?
- Can You Get Chlamydia From Kissing?
- Can You Get Herpes From a Toilet Seat?
- Can You Get Herpes From Kissing?
- Can You Get an STI if You're Both Virgins?
Sources
- NHS — Sexual health conditions
- BASHH — UK clinical guidelines for STI management
- British HIV Association (BHIVA) — HIV treatment guidelines
- Terrence Higgins Trust — sexual health information
- UK Health Security Agency — STI surveillance data
Steve Page is a recognised expert on Sexually Transmitted Diseases (STDs) and STD treatments, having published numerous articles in peer-reviewed journals and presented his research at conferences around the world. He has an in-depth understanding of the latest medical research on STDs, and is an advocate for the development of new treatments and protocols to improve the health of those affected. In addition to his research, he has dedicated his career to understanding the causes and symptoms of STDs, as well as how to best treat those impacted.
