Thyroid dysfunction after delivery: incidence and clinical course.

In a prospectively planned study of 591 Danish women thyroid dysfunction after delivery was found in 23 (3.9%). Seven women were hypothyroid and 16 were thyrotoxic. In seven of the thyrotoxic subjects a hypothyroid phase followed. Thyroid dysfunction was mostly transient with complete resolution within a year but persisted in three women (13%). Three months after delivery a positive titre of thyroid microsomal antibodies (TMAb) was found in 38 women (6.4%). Positive titres of TMAb were more often found in women with thyroid dysfunction than in those without (20/38 vs. 3/553). Maximal TMAb titres were seen 5-6 months after delivery and were associated with the occurrence of hypothyroidism. Postpartum thyroid dysfunction was found more often in women with a personal or family history of autoimmune thyroid disorder.