Costs attributable to initiating antenatal screening were included. Specifically, the cost of an HIV test, the cost of zidovudine, the cost of neonatal-pediatric HIV and lifetime treatment, and the cost of early HIV detection were considered in the analysis. Quantities of resource use were not analysed separately from the costs. Costs were not discounted. Charges were used as proxies of costs for the zidovudine and HIV culture use. The quantity/costs boundary adopted was the hospital and the patient. The data were taken from sources dated 1988-1994. When necessary, costs were reflated to 1993 prices using the medical care component of the Consumer Price Index. Total costs were calculated using a model. The authors reported that costs of late maternal infection and acquired immunodeficiency syndrome were excluded, as it was assumed that clinical symptoms or indications would eventually lead such women to seek testing outside pregnancy.