HIV-positive women enrolled in a clinical trial testing two types of antiretroviral (ARV) therapy during pregnancy were highly likely to have a second pregnancy within two years of the first if they used only condoms as a contraceptive method, according to a study reported in a letter published in the June issue of The Journal of Acquired Immune Deficiency Syndromes.

Effective ARV therapy has significantly reduced the chance of an HIV-positive woman transmitting HIV to her baby during pregnancy and delivery. However, health care providers have recommended that HIV-positive women taking ARV therapy use effective contraception to avoid pregnancy due to the possibly toxic effects of the drugs on babies, especially during the first three months of pregnancy.

To explore the rate and reasons for unplanned, repeated pregnancies, Heather Watts, MD, from the Eunice Kennedy Shriver National Institute of Child Health and Human Development in Bethesda, Maryland, and her colleagues examined medical records of HIV-positive women enrolled in the Pediatric AIDS Clinical Trials Group (PACTG) 1022 study. Thirty-seven women participated in the study, which compared an ARV regimen including Viracept (nelfinavir) with a regimen containing Viramune (nevirapine). Over two years of follow-up, there were 11 subsequent pregnancies in nine women. Six women chose to carry the babies to term, while the remaining women had spontaneous or planned abortions. The rate of subsequent pregnancies in this study was twice that seen in two other large studies of HIV-positive women.

Watts’s team found that women with repeat pregnancies were similar to women who did not have repeat pregnancies in most demographic factors, such as pregnancy history, smoking or drug and alcohol use. All of the women with repeat pregnancies used only one method of contraception—condoms—while women without repeat pregnancies used two methods of contraception—either condoms plus hormonal contraceptives, or condoms plus sterilization.

The authors state that they did not explore the reasons women chose to use only condoms. They hypothesize, however, that women and their providers may have chosen not to use hormonal contraceptives due to concerns over drug interactions between ARV drugs and such contraceptives, or data from that period showing an increased risk of disease progression in women using oral birth control medications. Watt’s and her colleagues are encouraging further research exploring reasons for single contraceptive use in HIV-positive women.