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Infectious Diseases in Obstetrics and Gynecology
Volume 2 (1995), Issue 5, Pages 223-227
Basic Science Article

Teratogenic and Embryocidal Effects of Zidovudine (AZT) in Sprague-Dawley Rats

Division of Prenatal Diagnosis, Department of Obstetrics & Gynecology, University of Texas Southwestern Medical Center, 5323 Harry Hines Boulevard, Dallas 75235-9032, TX, USA

Received 22 August 1994; Accepted 15 November 1994

Copyright © 1995 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Objective: The purpose of the present investigation was to analyze the effets of zidovudine on the postimplantation embryo and fetus.

Methods: Pregnant Sprague-Dawley rats were given various doses (10 mg/kg, 30 mg/kg, 150 mg/kg) of zidovudine or saline by an endotracheal tube during the period of embryogenesis (days 6–8, 9–11, 6–11 postconception). The animals were sacrificed on days 18–19 of pregnancy, and their fetuses were removed by hysterotomy. Autopsies under low (15×) and high (40×) power light microscopy were performed on all fetuses.

Results: There was no statistically significant difference among the groups with respect to maternal weight gain. There were more pregnancy resorptions in the group receiving high-dose zidovudine (150 mg/kg/day) throughout embryogenesis than in the control group (P = 0.001, respectively). Four major structural anomalies were noted among the 689 fetuses examined, but zidovudine was not associated with an increased frequency of congenital anomalies in rats when it was administered in doses similar to, 3-, and 15-fold higher than the regimen recommended for adult humans. The drug, however, was embryocidal in the high-dose group (P = 0.002).

Conclusions: These findings are consistent with previous studies of preimplantation mouse embryos that demonstrated an embryocidal effect on preimplantation conceptuses. In summary, post-implantation embryonic zidovudine exposure was associated with significantly increased pregnancy losses (resorptions and intrauterine deaths).