Antinuclear antibodies, rheumatoid factor and C-reactive protein in serum of normal women using oral contraceptives.

To assess the effect of oral contraceptives on antinuclear antibodies (ANAs), rheumatoid factor (RF), and C-reactive protein (CRP), 3 groups of women were studied: 1) 174 women (ages 16-47) from the time of their initial uses of oral contraceptives, 2) 119 women (ages 17-39) selected from the community at random, and 3) 210 women (ages 17-47) who had been taking oral contraceptives prior to and continuing through the course of this study. Data from the original 174 were available for only 82 of the subjects. 4 women from this group of 82 with negative ANA tests prior to treatment developed positive ANAs (all took oral contraceptive combinations containing 80 mcg mestranol per tablet), 9 developed RF, and 30 developed CRP in less than a year. The prevalence of positive tests for ANA, RF, and CRP was greater in the initial group of 210 women who had been using oral contraceptives than that found in the initial group of 174 women who had not used oral contraceptives until the study. Cross-comparison of the 3 groups demonstrated no significant difference in the prevalence of positive tests for ANA. Data suggest that frequency of positive tests for ANA increases with chronological age. When group comparisons were made only the increase in CRP was statistically significant (p less than .05). Composition and dosage of oral contraceptives may have influenced the induction of antinuclear antibodies in the group of 82 women examined from initial use of oral contraceptives.