HAART and the Safety of the Fetus

In high-income countries, the widespread availability of highly active antiretroviral therapy (HAART) has dramatically decreased deaths from AIDS-related infections. As a result, HIV positive people in these countries are generally living longer, and some are thinking about having children.

Fortunately, HIV positive women can increase their chances of giving birth to a healthy, HIV negative baby, with several steps as follows:

• getting counselling before becoming pregnant
• receiving prenatal counselling and care
• taking HAART while pregnant so that viral load is as low as possible
• receiving intravenous AZT shortly before delivery
• having a C-section (Cesarean section)
• giving the infant six consecutive weeks of AZT after birth
• not breast-feeding, as breast milk contains HIV and can infect the baby

As a result of these steps, in high-income countries the risk of giving birth to an HIV positive baby is now less than 2%.

Drug Safety

Ever since the very unfortunate episode of birth defects as a result of the use of the tranquilizer thalidomide, pregnant women have been especially careful about protecting the fetus from the toxicity of medicines. Some pregnant HIV positive women may be concerned about the potential effect of HAART on the safety of the fetus. These concerns are reasonable because the results of experiments on mice and monkeys revealed that some anti-HIV drugs, particularly nukes (nucleoside analogues), can affect the genetic material (DNA) of the offspring of these animals. And if this effect holds true in human infants, there is the possibility of a long-term risk for cancer.

But it is important to bear in mind that humans are neither mice nor monkeys; that is, results of animal experiments are merely a guide and do not always accurately predict what will happen when people are given the same drugs. The wonderful news is that two large studies, one in the United Kingdom and the other in France, have found no increased risk of cancer or birth defects in children born to HIV positive women who used anti-HIV drugs during pregnancy.

In the following reports we review research on the effects of exposing the fetus to anti-HIV medicines. Overall, many years of research show that the immense benefit of HAART in pregnant HIV positive women continues to outweigh any theoretical risks to the fetus.

References

1. Townsend CL, Cortina-Borja M, Peckham CS, et al. Low rates of mother-to-child transmission of HIV following effective pregnancy interventions in the United Kingdom and Ireland, 2000-2006. AIDS. 2008 May 11;22(8):973-81.
2. Anderson BL, Cu-Uvin S. Pregnancy and optimal care of HIV-infected patients. Clinical Infectious Diseases. 2009; in press.
3. Olivero OA. Mechanisms of genotoxicity of nucleoside reverse transcriptase inhibitors. Environmental and Molecular Mutagenesis. 2007 Apr-May;48(3-4):215-23.
4. Poirier MC, Olivero OA, Walker DM, et al. Perinatal genotoxicity and carcinogenicity of anti-retroviral nucleoside analog drugs. Toxicology and Applied Pharmacology. 2004 Sep 1;199(2):151-61.
5. Wogan GN. Does perinatal antiretroviral therapy create an iatrogenic cancer risk? Environmental and Molecular Mutagenesis. 2007 Apr-May;48(3-4):210-4.
6. Thorne C, Newell ML. Safety of agents used to prevent mother-to-child transmission of HIV: is there any cause for concern? Drug Safety. 2007;30(3):203-13.
7. Benhammou V, Warszawski J, Bellec S, et al. Incidence of cancer in children perinatally exposed to nucleoside reverse transcriptase inhibitors. AIDS. 2008 Oct 18;22(16):2165-77.
8. Townsend CL, Willey BA, Cortina-Borja M, et al. Antiretroviral therapy and congenital abnormalities in infants born to HIV-infected women in the UK and Ireland, 1990-2007. AIDS. 2009; in press.

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