The decision of pregnancy for a woman with Rheumatoid arthritis (RA) requires considering the consequences of RA on conception and course of pregnancy but also on pregnancy on the course of RA. Fertility is not decreased in RA, however, fertility is lower in RA. Complications of pregnancy such as hypertension, preeclampsia or caesarean scar are more frequent in RA, although there is an increase that is fortunately unimportant. Pregnancy represents for two thirds of women with RA a period of calm with sometimes capricious course of the disease, despite the considerable reduction in the treatment. Several hormonal and immunological mechanisms explain this improvement.