Rheumatoid arthritis (RA) or Crohn's disease (CD) are both recognised indications of anti-tumour necrosis factor α treatment, indicating that these diseases may have important mechanisms in common, at least in part, through the contribution of the Th1/Th2 cytokine balance.1-3 The classical improvement of 75% of patients with RA during pregnancy suggests that pregnancy is a natural situation where this balance is modified.4 ,5 It is thus of interest to describe the clinical course of a patient with the association of two inflammatory diseases, RA and ulcerative colitis (UC) and its modulation by pregnancy.

Rectal bleeding and mild foot arthralgias started in a 36 year old woman with no particular personal or familial history one year before her first pregnancy. These symptoms remained …