Retention of IUDs: An International Comparison

A study of international scope on the retention rate of intrauterine devices (IUD) is presented. It is estimated that 3 million IUD insertions have been performed in Asia 100000 in the Middle East and North Africa and 150000 in Latin America during the period 1963-1966. Except for the U.s. about 67%-75% of the acceptors have 4 or more living children with the lower proportion prevailing in urbanized areas. IUD retention rates vary from about 55-80 per 100 users after 1 year of use while after 2 years of use excluding reinsertions the rate is about 43-65. 12-month pregnancy rates for the IUD vary from 1.1 per 100 users to 6.2 depending on the type and size of the device and the age of the acceptor. Expulsions decrease sharply with age and parity although age is the primary factor. 1st-year expulsion rates vary from about 1 per 11 users to 19 depending on the type and size of the device are parity and time. It is estimated that devices are reinserted in 60%-70% of the cases of an expelled device. Removal rates decrease with age parity and time but not to the extent that these factors influence expulsions. Data from the U.S. indicate a 12-month net removal rate ranging from 19 per 100 users under 25 years of age to 15 per 100 users 35 years of age or older. After the 1st year of use the incidence of removals for medical reasons seems to reflect the normal incidence of menstrual and other pelvic complaints. A mathematical formual is developed for measuring the probability of discontinuation and is applied to particular countries and to variables that may influence retention rates e.g. age parity type and size of device and insertions by physicians or paramedical personnel. It is estimated that the IUD programs in South Korea Taiwan and Pakistan will result in a reduction of the annual birthrates 3.7-5.3 3.0-5.0 and 1.0 per 1000 population respectively.