The pill, parity, and rheumatoid arthritis

Arthritis Rheum. 1990 Jun;33(6):782-9. doi: 10.1002/art.1780330604.


We report on a case-control study investigating the relationship of oral contraceptive pill (OCP) use and parity to the development of rheumatoid arthritis (RA). Women with RA were compared with 2 separate control groups, women with osteoarthritis (OA) and women randomly selected from a population-based electoral register. Nulliparity was found to be a risk factor for the development of RA, with age-adjusted odds ratios of 1.82 (95% confidence interval [CI] 1.09-3.03) versus the OA control group and 1.83 (95% CI 1.03-3.06) versus the population control group. Use of OCPs before the age of 35 was negatively associated with RA (odds ratio 0.56, 95% CI 0.29-1.12 versus the OA control group; odds ratio 0.6, 95% CI 0.30-1.17 versus the population control group). Some evidence of a duration-response effect was seen, although the numbers were small. The 2 variables were also multiplicative, with nulliparous non-OCP users having a 4-fold risk of RA compared with parous OCP users. These findings suggest that pregnancy and OCP use have a "protective effect" on the development of RA, although the mechanism remains unclear.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Arthritis, Rheumatoid / epidemiology*
  • Case-Control Studies
  • Contraceptives, Oral*
  • Female
  • Humans
  • Middle Aged
  • Osteoarthritis / epidemiology
  • Parity*


  • Contraceptives, Oral