The effect of pregnancy on the onset of psoriatic arthritis.

Pregnancy may be a risk factor for the development of arthritis. The effect of pregnancy and other hormone-associated events on the expression of psoriasis and arthritis was investigated retrospectively in 33 female patients with psoriatic arthritis. Eighteen per cent of patients or 30% of mothers had onset of arthritis within 3 months postpartum. Another 5 patients (15%) had perimenopausal onset of arthritis. No such temporal association was seen with the onset of skin psoriasis. Hormone-associated events appear to be as important modifiers of the arthritis associated with psoriasis as they are for other forms of joint disease.