Is poor pregnancy outcome a risk factor in rheumatoid arthritis?

Previous work has suggested that prior poor reproductive outcome may be a risk factor in rheumatoid arthritis (RA). A case-control study of 195 women with RA and 462 control women from two different sources is presented here. No increase in rates of spontaneous abortion was seen in the women with RA; indeed a protective effect was seen with an age adjusted odds ratio of 0.6 (95% confidence interval (CI) 0.4 to 0.9). A non-significant increase in stillbirth rates was seen in women with RA, producing an age adjusted odds ratio of 1.5 (95% CI 0.7 to 3.4). No differences in rates of induced abortion were seen. Thus although hormonal and gynaecological factors are undoubtedly important in the aetiology of RA, it was not possible to confirm that prior poor reproductive outcome is a risk factor in RA.