• pregnancy
• oral contraceptives
• rheumatoid arthritis

Rheumatoid arthritis (RA) is a disease with a markedly greater incidence in women,¹ suggesting perhaps the importance of sex hormones in disease susceptibility. Serum oestrogen levels are not, however, raised in women with RA,² although in animal studies they have been shown possibly to be proinflammatory.³ It is against this background that the consistent observation that oral contraceptive (OC) use is probably protective for development of RA is, at first sight, surprising.⁴ One explanation might be that it is not the use of OCs themselves that is important but rather that their use is associated with delaying or reducing the likelihood of pregnancy. The latter has been shown to be important as the postpartum period is a time of increased risk of disease onset.⁵

A separate question, however, emerges as to whether continuing OC use or subsequent pregnancy influences disease outcome in women who have already developed RA. This is an issue of practical relevance …