How likely is mother-to-child transmission?

  • With effective HIV treatment and a managed delivery, the risk of an HIV-positive woman passing HIV on to her baby is very low.
  • In the absence of any intervention, between a third and a half of infants will acquire HIV.

In the absence of any intervention, an HIV-positive woman has a 30 to 45% chance of transmitting the virus to her baby.

  • Approximately 5 to 10% of infants are infected during pregnancy.
  • Approximately 10 to 20% are infected during childbirth.
  • Approximately 10 to 20% are infected through breastfeeding.1

But with effective HIV treatment and a managed delivery, the risk of mother-to-child transmission (MTCT) can be greatly reduced. Transmission rates fell from about 20% in the UK and Ireland in 1993 to under 2% in 1998, as a result of the introduction of opt-out HIV testing in antenatal care, more extensive use of antiretroviral drugs during pregnancy and delivery, caesarean section for delivery and formula feeding of the baby.

Currently, the risk of mother-to-child transmission in the UK, for women who have been diagnosed and who receive the right advice and treatment is below 1%, with transmission rates for babies of women on combination therapy and a viral load of less than 50 copies/ml at 0.1%.2

Transmission of HIV-2 is less common than transmission of HIV-1. Mothers with HIV-2 are likely to have a lower viral load and slower disease progression. Between 0 and 4% of women with untreated HIV-2 pass on their infection.3

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References

  1. Lehman DA & Farquhar C Biological mechanisms of vertical immunodeficiency virus (HIV-1) transmission. Rev Med Virol 17: 381-403, 2007
  2. Townsend C et al. Low rates of mother-to-child transmission of HIV following effective pregnancy interventions in the United Kingdom and Ireland, 2000-2006. AIDS 22: 973-981, 2008
  3. Burgard M et al. Mother-to-Child Transmission of HIV-2 Infection from 1986 to 2007 in the ANRS French Perinatal Cohort EPF-CO1. Clin Infect Dis. 51: 833-843, 2010
This content was checked for accuracy at the time it was written. It may have been superseded by more recent developments. NAM recommends checking whether this is the most current information when making decisions that may affect your health.