Factors influencing contraception continuation rates: The oral and the intrauterine methods.

The technique of multi-sort analysis was used to compare the relative duration of use of oral and intrauterine contraception among low socio-economic groups in Baltimore City. The clinical records of over 12,000 women who had received contraception through the Baltimore public services were analyzed. The type of method a woman used was found to be the most important factor affecting her probability of continuing contraception. Her age, race, and how long she had been using the method also influenced this probability. The strictness of the criteria used for the definition of continuation rates and the fact that experience was incomplete for many intrauterine contraceptors probably in part explain the somewhat low continuation rates obtained for both methods. It is suggested that the intrinsic characteristics of each method may lead to a clinical impression favoring the oral even when statistical evidence, as presented here, favors the intrauterine method.