Pregnancy Outcomes in HIV Positive Women Taking Antiretroviral Drugs Prior to Conception

During the past decade, treatment for the prevention of vertical HIV transmission from mother to infant has incorporated the standard use of highly active anti-retroviral therapy (HAART). HAART involves a combination of three different types of antiretroviral drugs, as opposed to utilizing a single drug or just two drugs. Though in the past, single drug therapy was often used with a nucleoside reverse transcriptase such as AZT, many pregnant patients these days are placed on more than one antiretroviral medication to combat HIV by interrupting viral replication using multiple pharmacologic approaches. Some studies have found increased risks of low birth weight (LBW) and preterm delivery (PTD) among pregnancies in which HIV-infected women were taking HAART, while others have shown no difference. Not much information is known regarding the potential impact on infant birth weight or risk of PTD when antiretroviral therapy is started prior to conception. To address this concern, a research group in Brazil analyzed 696 pregnancies in HIV positive women to compare the infant birth weights and incidences of preterm delivery in women who were taking antiretroviral therapy prior to conception with those who did not start their antiretroviral therapy until after the first trimester of pregnancy.

A single HIV reference center in Rio de Janeiro which treats HIV positive pregnant women using a multidisciplinary team approach collected information on this group of patients after approval by the institution’s ethical committee. One-hundred and thirty patients (18.7%) conceived while taking antiretroviral therapy, of which 100 patients were taking HAART. Five hundred sixty-six women started antiretroviral therapy after the first trimester of pregnancy and served as the comparison group. Stratification of their cohort of patients by type and time of initiation of antiretroviral therapy demonstrated that use of HAART prior to conception was associated with 3.6 times increased risk for LBW and a 5 times increased risk of PTD. These values were deemed to be statistically significant even after adjusting for characteristics such as multiparity (prior birth), presence of hypertension, presence of STDs, and viral load greater than 10,000 at delivery. Similar risks for LBW or PTD were not seen with the use of dual therapy prior to conception.

Though this study suggests that preconceptional HAART may be associated with an increased risk of LBW or PTD, further examination of the groups in the study reveals that there were many more women (33.7% vs. 10.2 %, p<0.001) in the preconceptional antiretroviral group who had symptomatic disease --thereby requiring antiretrovirals for maternal health-- compared to the group of women who started antiretrovirals after the first trimester. Therefore, it may be the poorer health status of the pregnant women, and not the antiretrovirals they were taking, that was related to their risk of LBW and PTD. Important missing information which may also account for the differences between the groups was any history of prior preterm deliveries or a calculation of the patients’ body mass indices, as both of these are major risk factors for PTD and LBW. Though the increased risk for LBW and PTD in this study’s patients receiving HAART prior to pregnancy may not be directly attributable to timing of HAART administration, this article certainly highlights the need for additional studies monitoring adverse pregnancy outcomes in similar populations to attempt to identify modifiable risk factors and ultimately improve management in such women.

--Summarized by Barrett Robinson, MD, MPH

Barrett Robinson is a Maternal-Fetal Medicine Fellow at Northwestern Memorial Hospital, where he participates in the ongoing care of one of Illinois’ largest clinics exclusively servicing HIV-positive pregnant patients

Original Citation:
Machado, ES et al. “Pregnancy outcome in HIV-1 infected women receiving combination antiretroviral therapy prior versus after conception.” Sex Transm Inf published online 5 Nov 2008; doi:10.1136/sti.2008.032300.

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