Copyright © Lippincott Williams & Wilkins. Unauthorized reproduction of this article is prohibited. Maternal antiretroviral drugs during pregnancy and infant low birth weight and preterm birth Edgardo G. Szyld a , Eduardo M. Warley a , Laura Freimanis f , Rene ´ Gonin f , Pedro E. Cahn b , Guilherme A. Calvet c , Geraldo Duarte d , Victor H. Melo e and Jennifer S. Read g for the NISDI Perinatal Study Group  Objective: To determine the relationship between maternal antiretroviral regimens during pregnancy and adverse infant outcomes [low birth weight (LBW) and preterm birth]. The a priori hypothesis was that protease inhibitor (PI)-containing regimens are associated with an increased risk of LBW and preterm birth. Design: Prospective cohort study of HIV-1-infected women and their infants (NISDI Perinatal Study). Methods: Data were analysed from 681 women receiving at least one antiretroviral drug [in order of increasing complexity: one or two nucleoside reverse transcriptase inhibitors (1 – 2 NRTI), two NRTI plus one non-nucleoside reverse transcriptase inhibitor (NNRTI) (HAART/NNRTI), or two NRTI plus one PI (HAART/PI)] for at least 28 days during pregnancy, and who delivered live born, singleton infants with known birth weight and gestational age by 1 March 2005. Multivariable logistic regression modeling was used to assess the relationship of maternal ART with LBW and with preterm birth, adjusting for covariates. Results: The incidence of LBW and preterm birth, respectively, was 9.6% and 7.4% (1–2 NRTI), 7.4% and 5.8% (HAART/NNRTI), and 16.7% and 10.6% (HAART/PI). There was no statistically significant increased risk of LBW [adjusted odds ratio (AOR), 1.5; 95% confidence interval (95% CI), 0.7–3.2] or preterm birth (AOR, 1.1; 95% CI, 0.5–2.8) among women who received HAART/PI compared with women receiving 1–2 NRTI. Conclusions: Among a population of HIV-1-infected women in Latin America and the Caribbean, maternal receipt of PI-containing ART regimens during pregnancy was not associated with a statistically significant increase in risk of LBW or preterm birth. ß 2006 Lippincott Williams & Wilkins AIDS 2006, 20:2345–2353 Keywords: HIV-1, HAART, low birth weight, preterm, pregnancy Introduction An increasing proportion of HIV-1-infected women are receiving combination antiretroviral therapy regimens (ART), including HAART, during pregnancy for their own health or for prevention of mother-to-child transmission of HIV-1. Receipt of combination ART regimens is associated with a decreased risk of mother- to-child transmission of HIV-1 [1–6]. Higher rates of preterm birth [7–9] and low birth weight (LBW) [8–12] have been described among From the a Hosp Diego Paroissien, the b Hospital Juan Fernandez, Buenos Aires, Argentina, the c Hospital dos Servidores do Estado, Rio de Janeiro, the d School of Medicine, University of Sao Paulo, Ribeirao Preto, the e School of Medicine, Federal University of Minas Gerais, Belo Horizonte, Brazil, f Westat, Rockville, and the g Pediatric, Adolescent, and Maternal AIDS Branch, NICHD, NIH, DHHS, Bethesda, Maryland, USA. Correspondence to Dr E. Szyld, Gavilan 1086 (1406), Buenos Aires, Argentina. E-mail: ezyld@fibertel.com.ar * See Appendix for listing of study group members. Note: Presented in part at the 12th Conference on Retroviruses and Opportunistic Infections. Boston, February 2005 [abstract 806]. Received: 12 March 2006; accepted: 16 June 2006. ISSN 0269-9370 Q 2006 Lippincott Williams & Wilkins 2345