To examine fecundity prior to disease onset in women with rheumatoid arthritis (RA).
Two hundred fifty-nine RA patients with an opportunity for pregnancy were compared with 1,258 control women as part of a prospective case-control study of recent-onset RA in women.
A 12-month or longer interval to pregnancy was found in 42% of RA cases compared with 34% of controls (odds ratio = 1.44, 95% confidence interval 1.10, 1.91). This difference was not accounted for by an older age when attempting to become pregnant among the RA cases compared with the controls. The result was unrelated to rheumatoid factor or HLA-DR4 status.
Women with RA were found to have decreased fecundity prior to disease onset, compared with control women.