Relationship of oral contraceptive estrogen dose to age.

The authors analyzed extracts of the computerized Medicaid records of 81,968 patients with prescription billing claims for oral contraceptives from the states of Michigan and Minnesota in 1980. It was found that women aged 35-39 years were more than twice as likely to be recipients of high dose (over 50 micrograms) estrogen oral contraceptive preparations than women aged 15-19. There was an increase in the proportion of high dose estrogen recipients among oral contraceptive recipients for each successive five-year age group from 15-19 to 35-39 years in both states. These findings were similar to those from National Disease and Therapeutic Index data for the United States for 1980, and appear to indicate changing patterns of use in the past decade. The independent contributions of age and estrogen dose or their combined effect with respect to the risk for venous thrombosis, pulmonary embolism, or related diseases has not been assessed in prior studies. To the extent that current use of oral contraceptives with higher estrogen doses contributes to the age-related trend of morbidity and mortality rates among women aged 15-44 years, an opportunity for prevention exists by altering this pattern of use.