Information About the Safety of Combination Antiretroviral Treatment for Human Immunodeficiency Virus Infection During Pregnancy
October 20, 1998
During the early 1990s, before perinatal preventive treatments were available, an estimated 1,000-2,000 infants were born with HIV infection each year in the United States. Today, the United States has seen dramatic reductions in mother-to-child, or perinatal, HIV transmission rates. These declines reflect the widespread implementation of Public Health Service (PHS) recommendations made in 1994 and 1995 for routinely counseling and voluntarily testing all pregnant women for HIV in the United States, and for offering zidovudine (AZT, also called ZDV) to infected women during pregnancy and delivery, and for the infant after birth. (MMWR - July 7, 1995)
Soon after, the use of combination therapy including a new class of HIV drugs known as protease inhibitors (PIs) became available. Combination treatments for people with HIV/AIDS now usually include three or four antiretroviral drugs (such as AZT, 3TC, ddI, d4T combined with PIs). (MMWR - April 24, 1998) Thus, many HIV-infected pregnant women may need to take combination therapy (including a PI) for their own health. In 1998, the PHS provided health care providers with information for discussion with HIV-infected pregnant women to make informed decisions regarding the use of antiretroviral drugs during pregnancy. (MMWR - January 30, 1998) The use of antiretroviral drugs during pregnancy requires unique considerations, including 1) the potential need to change dosing as a result of changes associated with pregnancy, 2) the potential for adverse short- or long-term effects on the fetus and newborn, and 3) the effectiveness for reducing the risk for perinatal transmission. Data to address many of these considerations were not yet available at the time those recommendations were made; most are still not available. Clinical studies that looked at the use of HIV combination treatment among pregnant HIV-infected women were already underway.
Recent Reports of Premature Births and Birth DefectsRecently, results from a few small studies showed that some HIV-infected women on combination therapy were reported to have had higher than expected rates of premature births. Other ongoing studies have not shown these results. It is not known if the premature births are due to the women's use of HIV therapy. These women may have had other risk factors for premature births or birth defects in their children. A summary of some of these studies follows; not all studies have yet been published in the medical literature.
Perinatal Prevention Saves Lives!Studies continue to show that perinatal HIV prevention is making a difference, both in terms of lives and resources saved:
Where Do We Go From Here?
It is important to note that the cause of the premature births and birth defects among HIV-infected women who are on combination therapy is not known. Risks of premature births are known to be associated with multiple risk factors such as young maternal age, concurrent sexually transmitted diseases, drug use, and socioeconomic risk factors. Among HIV-infected women who have a number of these risk factors, the severity of their HIV illness is also likely to contribute to prematurity risk. Recent small studies have raised the question of whether combination therapy might be associated with this risk. Scientists are currently reviewing the combination treatment studies involving several cohorts to evaluate any maternal factors including therapy that may have contributed to the premature births. One such study is a collaboration with investigators from PACTS, NIH, CDC, and other institutions, which will consist of a meta-analysis of prematurity and combination therapy among HIV-infected women enrolled in U.S.-based cohort studies.
Until further information is known, it is recommended that HIV-infected pregnant women who are receiving combination therapy (with or without PIs) for treatment of their HIV infection should continue their regimens as recommended by their health care provider. These women should receive careful, regular monitoring of their pregnancies and for potential toxicities.
No changes have been recommended to the current treatment guidelines for pregnant women infected with HIV. These recommendations include the use of AZT primarily for the prevention of transmission of HIV to the infant. The recommendations also stress the need for discussion with the woman of the known and unknown short- and long-term benefits and risks of all drugs being considered for therapy for her and her infant.
PHS will provide updated information on this Web Site as it becomes available over the next several months.
This article was provided by U.S. Centers for Disease Control and Prevention. Visit the CDC's website to find out more about their activities, publications and services.