Which drug is recommended during pregnancy to reduce HIV transmission risk to the fetus?

Zidovudine (AZT) is recommended during pregnancy to reduce the risk of HIV transmission from an infected mother to her fetus. This antiretroviral medication has been shown to effectively lower the viral load in pregnant women living with HIV, which significantly diminishes the likelihood of passing the virus during pregnancy, labor, and delivery, as well as through breastfeeding. The use of zidovudine has become a standard part of HIV management in pregnancy due to its proven efficacy and safety profile.

Other drugs listed do not serve the purpose of reducing HIV transmission in pregnancy. Ribavirin, for instance, is primarily used to treat hepatitis C and respiratory syncytial virus (RSV) but is contraindicated in pregnancy due to its teratogenic effects. Acyclovir is an antiviral medication used for herpes simplex virus infections and is not indicated for HIV management. Tamiflu is an antiviral medication used to treat influenza and does not have a role in HIV therapy or prevention of transmission during pregnancy. Thus, zidovudine remains the drug of choice for this specific indication in pregnant women with HIV.