[Postpartum definitive hypothyroidism. 7 cases].

Seven cases of hypothyroidism developed within 6 months of delivery are reported. Radioimmunoassays regularly showed very low thyroxin levels and high thyroid-stimulating hormone levels, thus confirming that the thyroid deficiency was of peripheral origin. A significant rise in antimicrosomal or antithyroglobulin antibodies was noted in 5 cases. One patient had HLA-B8 and 4 had HLA-DR3, which was not significantly different from the prevalence in the regional population. In contrast with the transient post-partum hypothyroidism reported mainly in Japan, the condition proved to be permanent in 6 patients followed up for more than two years. The increased frequency of HLA-DR3 and 5 recently described in thyroiditis with transient post-partum thyrotoxicosis was not found in our series. It would appear that pregnancy, which is a period of immune incompetence, may disclose a latent lymphocytic thyroiditis.