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Zidovudine Pregnancy and Breastfeeding Warnings

Zidovudine is also known as: Retrovir

Zidovudine Pregnancy Warnings

In February 1994, early statistical analysis of ACTG 076 revealed that perinatal administration of zidovudine reduced the transmission of HIV from mother to infant by approximately two-thirds (8.3% compared to 25.5% with placebo). At this point, the trial was ended and zidovudine was offered to those participants receiving placebo. Zidovudine had been initiated in HIV-infected women with a CD4 cell count greater than 200/mm3 who had received no antiretroviral therapy during their current pregnancy and were between 14 and 34 weeks gestation. Zidovudine 100 mg five times a day was given for the duration of pregnancy. During labor, intravenous zidovudine was given, beginning with 2 mg per kg over the first hour, followed by 1 mg per kg per hour until delivery. For six weeks after birth, infants received 2 mg per kg orally every six hours, beginning at 8 to 12 hours of life. During this study zidovudine was administered to 180 infants. The only fetal or infant toxicity reported was a mean decrease in hemoglobin of less than 1 g/dL, which resolved spontaneously following completion of therapy. Zidovudine crosses the placenta, with similar maternal serum and umbilical concentrations at delivery. The pharmacokinetics of zidovudine are not significantly affected by pregnancy. Several reports of the use of zidovudine in pregnancy, including during the first trimester, have not revealed teratogenicity or fetal toxicity, other than reversible anemia. No adverse effects were observed in HIV-uninfected children with in utero and neonatal exposure to zidovudine followed up for as long as 5.6 years. One series of 104 cases of intentional or inadvertent use of zidovudine during all stages of pregnancy was unable to demonstrate any specific abnormalities reasonably attributable to zidovudine use. Anomalies reported in infants exposed during the first trimester included low set ears, retrognathia, prominent epicanthal folds, hirsutism, triangular facies with blue sclera, hyperpigmented skin macules, prominent sacral dimple in one infant, multiple minor anomalies in one infant, and extra digits in one infant. Pectus excavatum was reported in two infants exposed in the second and third trimesters. An infant exposed during the third trimester exhibited albinism, congenital ptosis, oligohydramnios and intrauterine growth retardation. An Antiretroviral Pregnancy Registry has been established to monitor maternal-fetal outcome of zidovudine exposures during pregnancy. To register patients, physicians should call 800-258-4263 (USA).

Zidovudine has been assigned to pregnancy category C by the FDA. Animal studies failed to reveal evidence of teratogenicity, although some studies demonstrated an increased incidence of fetal resorption. There are no controlled data in human pregnancy. Early results from a study by the AIDS Clinical Trial Group (ACTG 076) indicated perinatal zidovudine administration reduced the incidence of HIV maternal-infant transmission from 25.5% to 8.3%. However, the long-term effects of zidovudine therapy during pregnancy are not known. Zidovudine should only be given during pregnancy when benefit outweighs risk.

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Zidovudine Breastfeeding Warnings

Zidovudine is excreted into human milk. The manufacturer recommends that due to the potential for serious adverse reactions in nursing infants, mothers should not breast-feed while taking zidovudine. The U.S. Public Health Service Centers for Disease Control and Prevention advise HIV-infected women not to breast-feed to avoid postnatal transmission of HIV to a child who may not yet be infected.

After administration of a single dose of 200 mg zidovudine to thirteen HIV-infected women, the mean concentration of zidovudine was similar in human milk and serum.

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References for pregnancy information

  1. Chavanet P, Diquet B, Waldner A, Portier H "Perinatal pharmacokinetics of zidovudine." N Engl J Med 321 (1989): 1548-9
  2. Panel on Treatment of HIV-Infected Pregnant Women and Prevention of Perinatal Transmission. National Institute of Health "Recommendations for use of antiretroviral drugs in pregnant HIV-1-infected women for maternal health and interventions to reduce perinatal HIV transmission in the United States. Available from: URL:" ([2011 Sep 14]):
  3. Culnane M, Fowler MG, Lee SS, et al. "Lack of long-term effects of in utero exposure to zidovudine among uninfected children born to HIV-infected women." JAMA 281 (1999): 151-7
  4. Taylor U, Bardeguez A "Antiretroviral therapy during pregnancy and postpartum." Am J Obstet Gynecol 166 (1992): 390
  5. Centers for Disease Control and Prevention "Zidovudine for the prevention of HIV transmission from mother to infant." MMWR Morb Mortal Wkly Rep 43 (1994): 285-7
  6. "Product Information. Retrovir (zidovudine)." Glaxo Wellcome, Research Triangle Park, NC.
  7. Delke I, Greenhaw J, Sanchez-Ramos L, Roberts W "Antiretroviral therapy during pregnancy." Am J Obstet Gynecol 168 (1993): 424
  8. Viscarello RR, DeGennaro NJ, Hobbins JC "Preliminary experience with the use of zidovudine (AZT) during pregnancy." Am J Obstet Gynecol 164 (1991): 248
  9. "Drugs for HIV infection." Med Lett Drugs Ther 43 (2001): 103-8
  10. Kumar RM, Hughes PF, Khurranna A "Zidovudine use in pregnancy: a report on 104 cases and the occurrence of birth defects." J Acquir Immune Defic Syndr 7 (1994): 1034-9
  11. Cullen MT, Delke I, Greenhaw J, Viscarello RR, Paryani S, Sanchez-Ramos L "HIV in pregnancy: factors predictive of maternal and fetal outcome." Am J Obstet Gynecol 166 (1992): 366
  12. Gillet JY, Garraffo R, Abrar D, Bongain A, Lapalus P, Dellamonica P "Fetoplacental passage of zidovudine." Lancet 2 (1989): 269-70
  13. Sperling RS, Stratton P, O'Sullivan MJ, et al. "A survey of zidovudine use in pregnant women with human immunodeficiency virus infection." N Engl J Med 326 (1992): 857-61
  14. Ferrazin A, De Maria A, Gotta C, Mazzarello G, Canessa A, Ciravegna B, Cirillo C, Melica F, Terragna A "Zidovudine therapy of HIV-1 infection during pregnancy: assessment of the effect on the newborns." J Acquir Immune Defic Syndr 6 (1993): 376-9
  15. Sperling RS, Roboz J, Dische R, et al "Zidovudine pharmacokinetics during pregnancy." Am J Perinatol 9 (1992): 247-9
  16. O'Sullivan MJ, Boyer PJ, Scott GB, et al. "The pharmacokinetics and safety of zidovudine in the third trimester of pregnancy for women infected with human immunodeficiency virus and their infants: phase I acquired immunodeficiency syndrome clinical trials group study (protocol 082)." Am J Obstet Gynecol 168 (1993): 1510-6
  17. Connor EM, Sperling RS, Gelber, et al. "Reduction of maternal-infant transmisssion of human immunodeficiency virus type 1 with zidovudine." N Engl J Med 331 (1994): 1173-80

References for breastfeeding information

  1. Newell ML, Dunn D, Peckham CS, Ades AE, Pardi G, Semprini AE "Risk factors for mother-to-child transmission of HIV-1." Lancet 339 (1992): 1007-12
  2. Panel on Treatment of HIV-Infected Pregnant Women and Prevention of Perinatal Transmission. National Institute of Health "Recommendations for use of antiretroviral drugs in pregnant HIV-1-infected women for maternal health and interventions to reduce perinatal HIV transmission in the United States. Available from: URL:" ([2011 Sep 14]):
  3. "Product Information. Retrovir (zidovudine)." Glaxo Wellcome, Research Triangle Park, NC.
  4. Fairbrothers D, Kirby E, Lester RM, Wegmann PC, Marshall F, Parkin WE "Recommendations for assisting in the prevention of perinatal transmission of human T-lymphotropic virus type III/lymphadenopathy-associated virus and AIDS." MMWR Morb Mortal Wkly Rep 34 (1985): 721-34
  5. "Infant feeding and transmission of human immunodeficiency virus in the United States." Pediatrics 131 (2013): 391-6

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