Effects of daily intake of zidovudine-stavudine on rat pregnancy outcome: biological essay.

Purpose: To evaluate the effects at term of a highly active antiretroviral drug association when administered for the whole period of rat pregnancy.
Methods: Forty pregnant rats weighing about 200 g were randomly divided into four groups: a control group (Ctr = drug vehicle control, n=10) and three experimental groups, which were treated with an oral solution of zidovudine-stavudine (Explx = 10/1 mg/kg b.w., n=10; Exp3x = 30/3 mg/kg b.w., n=10; Exp9x = 90/9 mg/kg b.w., n=10) from "day 0" up to the 20th day of pregnancy. Maternal body weights were recorded at the start of the experiment and on the 7th, 14th and 20th day thereafter. At term (20th day) the rats were anesthetized and submitted to hysterotomy. Implantations, reabsorptions, living fetuses, placentae and intrauterine deaths were looked for and recorded. The collected fetuses and placentae were weighed and the concepts were examined by a stereoscopic microscope looking for external malformations.
Results: No significant alterations due to the antiretroviral drug treatment could be detected regarding the number of implantations, fetuses, placentae, absorptions and malformations nor regarding maternal and fetal mortality.
Conclusions: Administration of the association zidovudine/stavudine for the whole period of rat pregnancy did not interfere with the maternal, fetal and placental weight gain as well as abnormalities detectable by the employed methodology.