Pregnancy and the risk of developing rheumatoid arthritis

Some studies suggest that the use of oral contraceptives (OC) may protect against the development of rheumatoid arthritis (RA) in women, a joint disease characterized by inflammation of the joints, stiffness, swelling, overgrowth of cartilage tissue, and pain. The relationship between behavioral factors related to OC use and a possible preventive effect of OC on RA development was assessed. Past pregnancy, age at first pregnancy, and pregnancies with unfavorable outcomes were evaluated as possible risk factors for RA. The study included 135 young women with recently diagnosed RA and 378 women with soft tissue rheumatic disorders or osteoarthritis, a chronic joint disease characterized by destruction of joint cartilage and bone overgrowth with malformation and impairment of function. The women were studied over a period of two years. The risk of RA was decreased in women who had been pregnant, and was lower in women who had early first pregnancies as compared with women who had late first pregnancies. The risk of RA was not substantially reduced if the pregnancy had an unfavorable outcome (ending before 25 weeks gestation). The protective effect of pregnancy against the development of RA was not related to OC use, nor was it related to the presence of a specific histocompatibility antigen, HLA-DR4, a cell element that can activate an immune response, or to a family history of RA. Hormonal changes during pregnancy may influence immune responses and thereby protect against RA. (Consumer Summary produced by Reliance Medical Information, Inc.)