[Preliminary study on the transport of AZT (Retrovir-zidovudine) through the placenta]

The authors selected six patients who were HIV positive and who had requested termination of pregnancy to study the passage of zidovudine through the placenta. After the patients had been warned about the procedure and given consent, 1 gram of zidovudine (Azitothymine) was given in five doses of 200 mg each orally. Ethical Committee consent had been obtained. At a mean age of 17.5 weeks of amenorrhoea, samples were taken from the mothers' blood, from the amniotic fluid and from the fetal blood between one and two hours and forty five minutes after the last dose of AZT had been taken. Pregnancy was terminated immediately after the amniotic fluid had been obtained. The levels of zidovudine and its metabolite glucuronide (G-AZT) were carried out using High Performance Liquid Chromatography (HPLC). The concentrations of the drug in the liquor and in the fetal blood were higher or equalled those found in the maternal blood. This makes it likely that the half life elimination was longer and the metabolism of the product slower when it had been metabolised to glucuronide. This study does not concern the teratogenic effect or the toxicity for the fetus. The drug remains contra-indicated in pregnancy. There is no proposal at present to use it to lessen transmission of the virus from the mother to the fetus.