Methods and Applications of Statistics in Clinical Trials, Volume 1: Concepts, Principles, Trials, and Designs

Chapter 43

Mother to Child Human Immunodeficiency Virus Transmission Trials

David E. Shapiro

43.1 Introduction

Mother-to-child transmission (MTCT) of human immunodeficiency virus type 1 (HIV) can occur through three major routes: through the placental barrier during gestation (in utero and antepartum), via contact with maternal bodily fluids during labor and delivery (intrapartum), and by ingestion of breast milk after delivery (postpartum); most MTCT is believed to occur close to the time of or during childbirth [1]. Infants who have a positive HIV test within the first 72 hours of life are presumed to have been infected in utero, and those who are HIV-negative within the first 72 hours and HIV-positive thereafter are presumed to have been infected close to or during delivery (or via early breastfeeding, if the infant breastfeeds).

Prevention of MTCT (PMTCT) is one of the most successful areas in HIV clinical research. Interventions to prevent MTCT have been developed for two different settings: the United States and other developed countries with access to medications, medical infrastructure, and safe replacement feeding so that breastfeeding can be discouraged; and resource-limited countries with limited access to medications and clean water, and where breastfeeding is critical [2]. In the absence of intervention, the risk of MTCT is approximately 15–25% during pregnancy through delivery [3], and an additional 0.9% per month during breastfeeding [4]. With combination antiretroviral ...