HIV in Pregnancy

The numbers, and how far they have moved

The NHS Infectious Diseases in Pregnancy Screening handbook sets out the trajectory. The risk of vertical transmission "when HIV is untreated in pregnancy is around 25%". Since universal antenatal HIV screening was introduced in 1999, rates "have declined significantly from 2.1% in 2000 to 2001 to under 0.4% since 2012".

The handbook attributes that to a combination of antenatal screening, high uptake of early and effective antiretroviral therapy, and optimised care before, during and after birth. Screening coverage in England was 99.8% across all regions in 2021 to 2022.

Two more context figures from the same source. Around 90% of pregnancies since 2016 have been to women who already knew their HIV status before conceiving, compared with 72% in 2007 to 2011. And the number of pregnancies to women known to be living with HIV has fallen from a peak of over 1,300 a year in 2006 to 2010 to below 1,000 in the years since 2016.

What happens after a positive result

The IDPS pathway timeframes apply to HIV as they do to hepatitis B and syphilis. Laboratory results should reach maternity services within 8 working days. A confirmed positive result should be followed by an appointment offered within 5 working days of the maternity service being notified. Women already known to be living with HIV who decline re-screening should still be offered an appointment within 5 working days of the screening team becoming aware of their status.

The handbook also says that all women with a confirmed positive result "must be referred to specialist services after receiving their results regardless of any past results or treatment", and that everyone who screens positive is added to a perinatal infectious diseases multidisciplinary team caseload. Management should follow British HIV Association guidelines.

Treatment, and what it is aiming at

The objective is full viral suppression, where the virus becomes undetectable in blood. The handbook describes regular viral load testing through pregnancy to monitor progress, with antiretroviral therapy started early for those not already on it, and continued for life thereafter, which reduces long-term health problems and onward transmission as well as protecting the baby.

RCOG's patient information adds the practical shape of your care: a team including an HIV doctor, an obstetrician, a specialist midwife and a paediatrician, with monitoring of viral load and CD4 count and of drug levels where relevant, and possible extra ultrasound scans. This page names antiretroviral therapy without doses; the regimen is chosen and adjusted by your HIV team.

How you give birth

This is where the guidance has changed most, and where old information does real harm.

The IDPS handbook states: "where full viral suppression is achieved, the risk of HIV transmission during delivery is the same regardless of whether a woman has a vaginal delivery or a caesarean section and so for most women, HIV should not impact decisions about the method of delivery."

In other words, an undetectable viral load means your birth options are your birth options. Older material, including some patient leaflets still in circulation, describes caesarean birth as a routine part of HIV care in pregnancy. That reflects the era before reliable viral suppression. If you are told a caesarean is necessary, the question to ask is what your viral load is and what it is expected to be at term.

Infant feeding: the honest current position

This is genuinely nuanced and deserves to be reported without smoothing. The handbook states that HIV is carried in breastmilk and can be transmitted through breastfeeding, that treatment significantly reduces the risk but that this "is yet to be quantified", and that for women on treatment with a consistently undetectable viral load "the risk is likely to be low, but it is not zero".

It then sets out BHIVA's position: BHIVA "continue to advise that formula feeding is the safest feeding option as it eliminates the risk of HIV transmission following delivery", while highlighting the importance of early discussion around infant feeding and advocating that "women who are virologically suppressed to be supported if they wish to breastfeed", with early planning and close monitoring by the multidisciplinary team.

Both halves of that are the official position at once. Formula eliminates the risk; supported breastfeeding is an option for virologically suppressed women. If you want to breastfeed, raise it early in pregnancy rather than after birth, because it requires a monitoring plan.

The extra tests you will be offered

RCOG's patient information lists additional screening for women living with HIV beyond the routine booking bloods: tests for hepatitis C, varicella zoster, measles and toxoplasmosis in addition to the usual hepatitis B, rubella and syphilis. Vaccinations against hepatitis B if you are not immune, plus pneumococcal and seasonal influenza vaccines, are recommended and described as safe in pregnancy. Live vaccines including MMR and varicella are given after birth rather than during pregnancy.

RCOG also notes that certain HIV medications in early pregnancy may prompt a gestational diabetes test between 24 and 28 weeks, and that vaginal swabs are offered early in pregnancy and again around 28 weeks, with treatment of any infection found.

Confidentiality and support

Your HIV status is health information like any other and is shared only with the clinical team involved in your care. The handbook emphasises that continuity of care from screening midwives and infectious diseases specialists makes a measurable difference for this group, and points to peer support including Positively UK's mentor mothers and CHIVA for children and families. The NHS pages on HIV and AIDS, and ACOG's patient information on HIV and pregnancy, cover the same ground for readers outside the UK system.