Can HIV be transmitted from a mother to her baby and how to avoid?

If a pregnant woman is infected with HIV, she can transmit the virus to her baby during pregnancy, labour and delivery, or breastfeeding. Without treatment, around 15-30 percent of babies born to HIV-infected women will become infected with HIV during pregnancy and delivery. A further 5-20 percent will become infected through breastfeeding.

Modern drugs are highly effective at preventing mother-to-child transmission of HIV. When combined with other interventions, including formula feeding, a complete course of treatment can cut the risk of transmission to below 2 percent. Even where resources are limited, a single dose of medicine given to mother and baby can cut the risk in half.

A woman who knows that she or her partner is HIV positive before she becomes pregnant can find out about interventions that may be able to protect herself, her partner or her baby from becoming infected with HIV. Doctors will be able to advise which interventions are best suited to her situation, and whether she should adjust any treatment she is already receiving if she is HIV positive.

There are a number of interventions that can reduce the risk of HIV transmission between a couple when attempting to conceive a child. If a couple decide they want to conceive a child through unprotected sex, they should first seek advice on how to limit the risk to each other and to their baby. It is worth noting that someone is less likely to transmit HIV if they are receiving effective antiretroviral treatment, and also if neither they nor their partner has any other sexually transmitted infections.

• If the woman is HIV positive and the man is HIV negative

An HIV positive woman and an HIV negative man can conceive without HIV transmission occurring by using artificial insemination (the process by which sperm is placed into a female's genital tract using artificial means rather than by natural sexual intercourse). This simple technique provides total protection for the man, but does nothing to reduce the risk of HIV transmission to the baby.

• If the man is HIV positive and the woman is HIV negative

Sperm washing is a process used to prevent HIV transmission from an HIV positive man to his partner during conception. Sperm washing involves separating sperm cells from seminal fluid, testing these cells for HIV, then inserting the cells into the woman's womb (intrauterine insemination), or directly into the egg (in vitro fertilisation or intracytoplasmic sperm injection). Sperm washing is a very effective way to reduce the risk of HIV transmission during conception, but it is not widely available and can be difficult to access, even in well resourced countries. Alternatives to sperm washing have been researched, such as the method of using pre-exposure prophylaxis and timed intercourse when the HIV-positive male partner is taking antiretroviral drugs.

• If both man and woman are HIV positive

When both partners are HIV positive, it might still be sensible for them not to engage in frequent unprotected sex, because there might be a small risk of one re-infecting the other with a different strain of HIV.