HLA-DR factors associated with postpartum hypothyroidism: an early manifestation of Hashimoto's thyroiditis?

Thirty-three Danish women selected from a prospective study of postpartum thyroiditis were HLA-DR typed. All women had positive titers of antimicrosomal antibodies, and 20 women developed thyroid dysfunction after delivery. DR5 and the phenotype 4.5 were significantly increased in the whole group (p less than 0.001) and strongly associated to hypothyroidism (p less than 0.01), whereas DR3 was insignificantly increased in thyrotoxic women. It is concluded that postpartum hypothyroidism is an autoimmune disorder and may be an early manifestation of Hashimoto's thyroiditis.