The post partum period and the onset of Graves' disease: an overestimated risk factor.

OBJECTIVE: Aggravation of autoimmune diseases due to a rebound reaction to the pregnancy-associated immune changes is common during the post partum (PP) period. Previous studies demonstrated that up to 45% of women developing Graves' disease (GD) in the childbearing age had a PP onset of disease. Thus, the PP period was identified as a major risk factor for GD onset. DESIGN: The aim of this study was to evaluate the role of the PP period as a risk factor for GD occurrence. METHODS: The reproductive histories of 291 consecutive GD patients (165 patients in the childbearing age and 126 in the non-childbearing age) were retrospectively collected. RESULTS: The rate of PP onset of GD in all patients with at least one successful pregnancy was 9.8 and 20.0% when only patients in the childbearing age were considered. In the entire cohort of GD women, independent of their age and parity status (i.e., the number of successful pregnancies), the rate of PP onset of GD was 7.2%. The relative frequencies of the rate of PP onset of GD were similar in relation with increasing parity. The rates of false negative (nulliparous) and false positive (parous non-childbearing+childbearing with a non-PP onset of GD) were estimated. The positive predictive value of the PP period for the onset of GD was less than 10%. CONCLUSIONS: The results of the current study would not support a role for the PP period as a major risk factor for de novo occurrence of GD.