HIV in pregnancy: treatment, birth and protecting your baby

HIV can be passed from mother to baby during pregnancy, at birth, or through breastfeeding or chestfeeding. The NHS pregnancy infections page makes clear that without treatment this is a real possibility, which is why antenatal screening and timely treatment are a central part of UK maternity care.

The RCOG emphasises that the most important protections are effective antiretroviral therapy, attention to the viral load and decisions about birth and feeding made with the HIV team.

All pregnant women are offered HIV screening at booking, and Tommy's notes that it is part of routine care. Screening alongside hepatitis B and syphilis means that conditions that can be treated to protect the baby are found early. The RCOG adds that other infections, including hepatitis B and C, rubella, syphilis and toxoplasmosis, are checked in women found to have HIV.

A positive screening result is confirmed by a second test and followed quickly by an appointment with a specialist HIV team, usually within days.

The RCOG recommends combination antiretroviral therapy in pregnancy, using several medicines together to bring the viral load down. Women who are already taking treatment usually continue it, with a review of the regimen. Women diagnosed in pregnancy start treatment soon after diagnosis, and the RCOG describes starting typically between 14 and 24 weeks depending on circumstances.

The aim is an undetectable viral load by late pregnancy. Tommy's says transmission through sex becomes impossible if the viral load is undetectable, and the risk to the baby falls to less than 1 in 1,000 when guidance is followed. Do not stop medicine without advice, and tell the team about any missed doses or side effects.

The RCOG explains that viral load near term guides the mode of birth. With a viral load below 50 copies per mL on treatment, and a good CD4 count, a vaginal birth is expected. Viral loads in the middle range often lead to the recommendation of a planned caesarean at around 38 weeks, and higher values make caesarean more strongly advised.

Intravenous zidovudine may be used around the time of birth in some situations. The detailed plan is set by the HIV and obstetric teams and updated as late pregnancy tests come back.

According to the RCOG, babies receive antiretroviral medicine within hours of birth, continued for several weeks, with duration depending on risk. The NHS says babies receive medicine for 2 to 4 weeks, and the RCOG describes 4 to 6 weeks in its guidance, so the exact length depends on the local protocol and the baby's risk.

Testing is done in the first days, again around 6 weeks, and 12 weeks, with final confirmation later, up to 18 months in Tommy's summary. A negative result at these tests gives reassurance, and many families are surprised by how routine the process becomes.

The RCOG states that formula is the safer choice and that avoiding breastfeeding is the single most effective way of reducing the risk of transmission. The NHS says formula feeding is recommended but that breastfeeding may be possible when the viral load is undetectable. Tommy's likewise says that with controlled HIV and medicine the risk of breastfeeding is minimal.

This is a decision to talk through with the HIV team and your midwife during pregnancy. If you choose to breastfeed, regular viral load monitoring and baby testing are part of the plan, and support with feeding should be offered whichever way you decide.

• Ask which option the HIV team recommends in your circumstances and why.

• Ask about support with formula feeding, including how it is provided.

• If you plan to breastfeed, ask about monitoring for you and your baby.

HIV care in the UK is confidential, and information is shared within the clinical team only with your agreement. Peer support organisations, including those mentioned by the NHS such as Positively UK and Terrence Higgins Trust, can offer practical and emotional help. Ask your HIV team about psychological support too, as a new diagnosis during pregnancy can be overwhelming. Contact your maternity unit urgently for reduced baby movements, fever, leaking fluid or bleeding, as for any pregnancy.