Pregnancy

AZT (zidovudine, Retrovir) is the only anti-HIV drug that is fully approved for use during pregnancy.

Current guidelines from the British HIV Association recommend that pregnant women take the anti-HIV drugs they require regardless of their pregnancy, with the exception of efavirenz (Sustiva).1 However, women who would otherwise not require HIV therapy due to high CD4 cell counts and low viral loads, can reduce the chance of mother-to-baby transmission by taking AZT during pregnancy and labour.2 3 4 Current guidelines recommend AZT monotherapy in women with HIV viral loads below 10,000 copies/ml and wild-type virus who do not require or want to take antiretroviral therapy during pregnancy and are willing to deliver by caesarean section prior to the onset of labour.

AZT monotherapy should begin in the third trimester of pregnancy, at a dose of 100mg five times per day. During labour, AZT should be administered intravenously at 2mg/kg over one hour, followed by 1mg/kg per hour until the umbilical cord is clamped. The baby should then be given 2mg/kg AZT by mouth every six hours starting within twelve hours of birth, until six weeks of age. For babies that cannot be given the oral solution, AZT should be given intravenously at 1.5mg/kg, infused over 30 minutes, every six hours.5 6

There are no serious short-term side-effects of AZT monotherapy for the mother or the child, and studies have found no long-term effects of AZT treatment before or during birth on birth defects, growth, development or risk of tumours in uninfected babies.7 8 9 10 11 Preliminary findings also suggest there is no difference in the risk of disease progression between women who take AZT and who take a placebo, after 18 months follow-up.12 However, there is some evidence that babies who do become infected after AZT exposure may have worse outcomes than HIV-positive babies who do not receive AZT before or during birth.13 14 Further studies following mothers and babies are underway.

Although breastfeeding by HIV-positive women is not recommended, mothers given AZT during birth also tend to have lower viral loads in their breastmilk, thereby further reducing the chances of transmission to breastfed infants. However, when women stop taking AZT, there is a burst in viral load, which may increase infant exposure to the virus.15

The addition of nevirapine (Viramune) to short-course AZT for the mother or baby may further reduce the chance of mother-to-child transmission of HIV. For further information on the use of antiretroviral drugs to prevent mother-to-child transmission of HIV, see Prevention of mother-to-child transmission.

References

  1. Hawkins D et al. Guidelines for the management of HIV infection in pregnant women and the prevention of mother-to-child transmission of HIV. HIV Med 6: S107-S148, 2005
  2. Mandelbrot L et al. Perinatal HIV-1 transmission: interaction between zidovudine prophylaxis and mode of delivery in the French Perinatal Cohort. JAMA 280: 55-60, 1998
  3. Centers for Disease Control and Prevention (CDC) Trends in sexual risk behaviors among high school students – United States, 1991-1997. MMWR, 47:749-752, 1998
  4. Larbalestier et al. Drug resistance is uncommon in pregnant women with low viral loads taking zidovudine monotherapy to prevent perinatal HIV transmission. AIDS 17: 2665-2667, 2003
  5. Connor EM et al. Reduction of maternal-infant transmission of human immunodeficiency virus type 1 with zidovudine treatment. N Engl J Med 331: 1173-1180, 1994
  6. Centers for Disease Control and Prevention (CDC) Recommendations of the U.S. Public Health Service Task Force on the use of zidovudine to reduce perinatal transmission of human immunodeficiency virus. MMWR Recomm Rep 43: 1-20, 1994
  7. Connor EM et al. Long term effect of zidovudine (ZDV) exposure among uninfected infants born to HIV-infected mothers in pediatric AIDS Clinical Trials Group (ACTG) protocol 076. 35th Interscience Conference on Antimicrobial Agents and Chemotherapy, San Francisco, abstract I1, 1995
  8. Lipshultz SE et al. Absence of cardiac toxicity of zidovudine in infants. N Engl J Med 343: 759-766, 2000
  9. Hanson EC et al. Lack of tumors in infants with perinatal HIV-1 exposure and fetal / neonatal exposure to zidovudine. J Acquir Immune Defic Syndr Hum Retrovirol 20: 463-467, 1999
  10. Brouwers P et al. Effect of continuous infusion zidovudine therapy on neuropsychological functioning in children with symptomatic human immunodeficiency virus infection. J Pediatr 117: 980-995, 1990
  11. Culnane M et al. Lack of long-term effects of in utero exposure to zidovudine among uninfected children born to HIV-infected women. JAMA 281: 151-157, 1999
  12. Bardeguez A et al. Lack of clinical or immunologic disease progression with transient use of zidovudine (ZDV) to reduce perinatal HIV-1 transmission in PACTG 076. Twelfth World AIDS Conference, Geneva, abstract 12233, 1998
  13. Italian Register for HIV Infection in Children. Rapid disease progression in HIV-1 perinatally infected children born to mothers receiving zidovudine monotherapy during pregnancy. AIDS 13: 927-933, 1999
  14. de Souza RS et al. Effect of prenatal zidovudine on disease progression in perinatally HIV-1-infected infants. J Acquir Immune Defic Syndr 24: 154-161, 2000
  15. Manigart O et al. Effect of perinatal zidovudine prophylaxis on the evolution of cell-free HIV-1 RNA in breast milk and on postnatal transmission. J Infect Dis 190: 1422-1428, 2004
This content was checked for accuracy at the time it was written. It may have been superseded by more recent developments. NAM recommends checking whether this is the most current information when making decisions that may affect your health.