Testing for HIV antibody at the antenatal clinic in Siriraj Hospital started on 1 July 1991. It was found that the percentage of HIV seropositive pregnant women rapidly increased from 1.2% in 1992 to 1.9% in 1993. During those 2 years, 487 seropositive women were admitted for delivery or abortion; 23.8% were adolescents and 47.0%, young adults. Prevention of HIV transmission from mother-to-baby was birth control; 95 women (19.5%) chose to abort their pregnancy. After termination of all pregnancies by abortion or delivery, 83% requested sterilization, 12.9% accepted Norplant, 1.8% the pill and only 2.3% refused anything at all. Condoms were used regularly for prevention of HIV infection by 29.4% of men although Thai men generally do not accept them for birth control. Seropositive Norplant users had more bleeding than general Norplant users but treatments were the same.