The use-effectiveness of two contraceptive methods in a Navajo population: the problem of program dropouts.

Navajo Indian intrauterine contraceptive device (IUD) and oral contraceptive users between 1966 and 1971 were followed up to estimate life table rates of complications and continuation. Because of high rates of dropping out, 41.6 per cent of 291 oral contraceptive users and 18.2 per cent of 534 IUD users, a 26 per cent sample survey of the dropout population was used to collate the dropout population data into the life table analysis. Estimates of the IUD continuation rates for one, two, and three years are similar to rates published elsewhere; however, continuation rates for the oral contraceptive are clearly lower than those for other populations, which only 33 per cent continuing after one year, 23 per cent after two years, and 12 per cent after three years. The IUD user is two to three times more successful than the oral contraceptive user in this population.