Transmission to a baby occurs when virus from an infected mother is passed on to the child in the womb, during delivery, or during breastfeeding. If the father is HIV-positive but the mother is not, the baby will not be directly infected from the father's sperm. If the woman becomes infected during conception there is considerable risk of transmission to the baby as the woman's viral load is likely to be high during seroconversion. 

Some couples who wish to conceive may try to minimise the risk of infecting the female partner by only having unprotected sex when the chances of pregnancy are high and HIV infectivity is low. This might be at a time when the woman is ovulating or when the partner's viral load is undetectable. However, the theory that this may be a less risky time for HIV transmission is unproven.

Sperm washing

One option for couples where the male is HIV-positive and the woman HIV-negative may be sperm washing. A semen sample can be `washed' by separating sperm and seminal fluid; the sperm sample is then incubated to allow live sperm to separate from dead sperm, and this sample can then be used for insemination. This method is likely to be more effective in individuals with an average or high sperm count. A study of 11 HIV-positive men found that this separation technique reduced viral load below the limit of detection (although this does not rule out the presence of a very low level of HIV), and no integrated proviral DNA could be recovered from the sperm samples either (Kim).

So far there have been no cases of HIV transmission to the female partner with this method (Semprini). The Italian group which pioneered this method reports more than 1000 insemination attempts for 350 couples, with 200 pregnancies as a result. Unfortunately, few centres in the UK offer this service and NHS funding remains limited. This method has been under investigation at the Chelsea and Westminster Hospital in London since 1999.

A woman wishing to conceive by this method will be monitored to determine when she is due to ovulate, and then her partner will be asked to provide a sperm sample which is washed before testing it for HIV. If the sample is negative, the insemination can proceed. The Chelsea and Westminster Hospital warns couples wanting to undertake the process that even after washing, around 5-6% of samples have tested HIV-positive.

So far, 53 HIV-1 positive men with seronegative partners have been treated at the Chelsea and Westminster Hospital. Following a sexual health and fertility screen on each partner, sperm washing was performed with intrauterine insemination (IUI). If a fertility problem is diagnosed, the couples receive IVF treatment. Data presented at the 9th British HIV Association Conference in April 2003 record 38 couples so far having had 94 cycles of IUI and 30 couples so far having had 42 cycles of IVF. (Gilling Smith)

All sperm samples are verified HIV-1 negative with NASBA assay before treatment. Ongoing pregnancy/live-birth rates per cycle were 10.6% (10/94) for IUI and 23.8% (10/42) for IVF. In total fifteen healthy children have been born with no seroconversions in either female partner or child on rigorous follow-up. Only five couples received NHS funding and over 40% of patients referred did not proceed to treatment for financial reasons.

One cycle of IUI costs six hundred and twenty-five pounds.

It is important to note that sperm washing is regarded as a risk-reduction process and not a fertility treatment. The technique is predicated on the understanding that couples desperate to have a family might be driven to risk the infection of the female partner in order for her to become pregnant. The Chelsea and Westminster researchers have highlighted the contribution of antiretroviral therapy to reducing the risk further.

Artificial insemination

Another option for a woman who is HIV–negative and whose partner is HIV–positive might be artificial insemination with another man's semen either from an anonymous donor, or someone known (such as a member of her partner's family). This is an option that many women use if their partner is infertile or risks passing on other infectious or congenital conditions.