[1] NYU, Sch Med, Dept Ob Gyn, New York, NY USA
[2] PharmaRes Corp, Wilmington, NC USA
[3] NICHHD, Pediat Adolescent Maternal AIDS Branch, Rockville, MD USA
[4] Univ N Carolina, Sch Publ Hlth, Chapel Hill, NC USA
[5] GlaxoSmithKline, Epidemiol, Res Triangle Pk, NC USA
[6] F Hoffmann La Roche & Co Ltd, Epidemiol, Nutley, NJ USA