To examine the risk of pregnancy loss in women with rheumatoid arthritis (RA).
Cumulative numbers of early miscarriages (before gestational Week 12), late miscarriages (weeks 12-22), and stillbirths reported to the Medical Birth Registry of Norway in the period 1999-2009.
There were 1578 women with RA and 411,130 reference women included in the study. Relative risks of early and late miscarriage in women with RA versus references were 1.2 (95% CI 1.1-1.3) and 1.4 (95% CI 1.1-1.7), respectively. There was no difference in stillbirth.
The risk of miscarriage was slightly higher among women with RA than in references.