HIV infection in utero

Last edited 03/2018

Around 1.4 million women diagnosed with HIV become pregnant every year

• HIV infection in pregnancy has become the most common complication of pregnancy in some developing countries (2)
• in 2009, an estimated 15.7 million women above the age of 15 were living with HIV globally, and 1.4 million of them became pregnant
• nearly 90% of these expectant mothers were living in 22 countries in sub-Saharan Africa and India (3)
• the prevalence of HIV infection in women giving birth in England and Scotland in 2008 was 1/486 (0.2%)
• this number has been stable since 2004 and has remained highest in London (3.7/1000)
• estimated proportion of exposed infants (born to both diagnosed and undiagnosed HIV-infected women) who became infected has decreased from 12% in 1999 to approximately 2% in 2007) (4)
• without any interventions, up to 45% of infants of HIV seropositive mothers are pre- or peri-natally infected with HIV (1), accounting for 90% of HIV infections in childhood
• in the developed world this figure may be lower, with vertical transmission rates of 20 - 30%.

Maternal viral load is the most predictive factor for perinatal HIV transmission.

• higher HIV viral load is associated with a greater risk of perinatal transmission
• however,transmission may occur with any viral load (even when the systemic plasma viral load is beneath the level of detection)(5)

When antiretroviral drugs are available as prophylaxis, HIV transmission can be reduced to less than 5% (3).

• zidovudine reduces the incidence of vertical transmission of HIV from about 26% to 8% when compared with controls (1).This treatment is effective regardless of the mother's viral load
• there is evidence that a short course of neviparine, in pregnant women with HIV-1 infection, was more effective than a short zidovudine regimen for reducing the risk of mother to child transmission of HIV-1 infection (6)

Caesarian section may halve the risk relative to normal vaginal delivery.

Signs and symptoms of HIV infection may be present in the fetus. The reported fetal abnormalities include wide set eyes, short nose, patulous lips, 'box' forehead and growth failure.

However the diagnosis is usually made between the ages of 6 months and 2 years. A common mode of presentation in children is progressive encephalopathy. The number of infant AIDS cases is increasing at an alarming rate.

• advice from the UK National Screening Committee on antenatal screening for HIV..click here

Reference:

• (1) Siemieniuk RAC et al. Antiretroviral therapy in pregnant women living with HIV: a clinical practice guideline. BMJ. 2017;358:j3961
• (2) World Health Organization (WHO) and United Nations Programme on HIV/AIDS (UNAIDS) 1998. HIV in pregnancy: A review
• (3) Joint United Nations Programme on HIV/AIDS (UNAIDS) 2011. Countdown to zero. Global plan towards the elimination of new HIV infections among children by 2015 and keeping their mother alive.
• (4) Royal College of Obstetricians and Gynaecologists (RCOG) 2010. HIV in Pregnancy, Management (Green-top Guideline No. 39)  
• (5) Rimawi BH et al. Management of HIV Infection during Pregnancy in the United States: Updated Evidence-Based Recommendations and Future Potential Practices. Infect Dis Obstet Gynecol. 2016;2016:7594306. 
• (6) Jackson JB et al. Intrapartum and neonatal single-dose nevirapine compared with zidovudine for prevention of mother-to-child transmission of HIV-1 in Kampala, Uganda: 18-month follow-up of the HIVNET 012 randomised trial. Lancet 2003;362: 859-68.