Hope of deliverance

Elective caesarean delivery, combined with an antiretroviral drug, can slash chances of infected mothers transmitting AIDS to their babies

Published: Monday 31 August 1998

-- ONE of the biggest threats that we face as we take the last few steps towards the new millennium is from acquired immunodeficiency syndrome, or AIDS. Spreading more rapidly than the proverbial wildfire, this universally-feared disease infects over 16,000 new victims every day. And in developing countries, the situation is worse. With health care facilities still in their infancy or altogether absent, many of these nations do not seem to stand a chance against the infection that has, within a short span of time, rivalled some of history's worst epidemics.

Though AIDS awareness campaigns in these nations have helped to a small extent, problems still thrive. And the biggest of them is preventing the deadly disease from being transmitted from AIDS-infected mothers to their newborn children.

A recent study by French experts, however, offers some hope. According to the study, pregnant women infected by the AlDS-causing human immunodeficiency virus (HIV) can dramatically reduce the chances of transmitting it to their newborns.

This, the study explains, can be done by having elective caesarean delivery while undergoing treatment with the antiretroviral drug zidovudine.

The prospective cohort study, the release of which was timed to coincide with the 12th world AIDS conference in Geneva, involved over 2,500 children born to mothers with HIV-1 infection - a variation of the feared virus.

The researchers, led by Laurent Mandelbrot of the Paris-based Cochin-Port Royal Hospital, found that of the 133 children delivered to HIV-infected mothers by elective caesarean section and in the presence of zidovudine prophylaxis, only one child was born with the virus. In contrast, among those mothers not receiving zidovudine treatment, the method of delivery made little difference to the rate of HIV transmission (British Medical Journal, Vol 317, No 7150).

The team found that among the 1,917 mothers who did not receive the zidovudine treatment, 17 per cent transmitted HIV-1 to their infants. Results varied among 902 mothers who received zidovudine treatment, depending on method of delivery.

Of the mothers undergoing an emergency caesarean delivery due to certain complications, 11 per cent transmitted the virus to their babies. And among mothers giving birth vaginally, seven per cent transmitted HIV-1.

For over four years zidovudine has been known to reduce perinatal (the latter half of foetal development) transmission of HIV.

In 1994, the AIDS Clinical Trials Group showed that a treatment regimen of zidovudine reduced perinatal transmission by up to an amazing 70 per cent.

Last February, the US Center for Disease Control and Prevention announced that transmission rates could be drastically reduced by a treatment regimen shorter in duration and less expensive than previously accepted. The impact the method of delivery has on transmission rates has been a topic of controversy.

Several studies show an increased risk of transmission associated with rupture of membranes before the onset of labour or more than four hours before delivery. Conversely, the conditions of events related to delivery - such as the length of labour, use of instruments for delivery, and episiotomy (a minor operation to facilitate childbirth) - seem to have little or no relation to transmission. Although caesarean section is one method for prevention of HIV transmission from mother to the foetus, Mandelbrot said "the decision should be made on an individual basis". "Because it has been known for several years that transmission occurs mainly at the end of pregnancy and during labour and delivery, elective caesarean section has already been recommended by many obstetricians in Europe, but was not a part of an consensus statement or official policy.

Until this year, evidence was quite contradictory," Mandelbrot said. "Unfortunately, caesarean section for the prevention of HIV transmission is not feasible, and even potentially hazardous, in several developing countries," he added.

A new initiative to reduce HIV transmission from mother to child in the developing nations was announced by the joint United Nations (UN) programme on HIV/AIDS earlier in July this year.

The US medicine giant Glaxo Wellcome said it will provide an initial supply of the drug and thereafter offer preferential pricing to the UN agency partners. Other aspects of the initiative include early access to adequate care, counselling and HIV testing.

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