Condom breakage during commercial sex in Chiang Mai, Thailand.

Used condoms in 30 female brothels in Chiang Mai, Thailand, during the period from August 1992 to October 1992 were examined for breakage. Data were also collected by interviewing 326 prostitutes who accounted for 65 percent of the total prostitutes providing condoms. The prostitutes had a mean age of 20.6 +/- 3.2 years. Sixty-one percent had no formal education. The median duration of prostitution was 13 months. The average number of clients per day in the past 24 hours and in the past 3 months was 4.4 +/- 2.5 and 5.5 +/- 2.2, respectively. Eighty-eight percent charged between $2 and less than $8 for their sexual service. All refused to practice oral or anal sex during the past 24 hours. Of 5,559 condoms, 298 were used two at a time and 15 were used three at a time. The breakage rate per act of intercourse was 5.9 percent (95% CI = 5.3, 6.5). The breakage per total condoms examined was 5.7 percent (95% CI = 5.1, 6.3). Breakage relating to manufacturing defect, i.e., pinholes, and that relating to use was 0.8 percent (95% CI = 0.6, 1.0) and 5.0 percent (95% CI = 4.4, 5.6), respectively. The probability of breakage when using two condoms at the same time was 3.4 percent (95% CI = 0.5, 6.3). Most of the breakage occurred at the distal part of the condom. There was no difference between the breakage rates of condoms provided by the brothels and those brought by the client; nor was there any difference between manufacturing defect or use. The breakage rate per client as estimated by prostitutes in the past 24 hours corroborated with that assessed by examination.