Economic appraisal.

if not identical with the painless thyroiditis occurring apart from pregnancy, which makes up at least 10% of all cases of hyperthyroidism in North America.'8 19 The histological appearances of the thyroid and serological changes favour an autoimmune origin, a view supported by the association of the syndrome with HLA-DR3 (as seen in Graves' disease and atrophic thyroiditis) and HLA-DR5 (as seen in Hashimoto's disease).20 Plainly patients with postpartum thyroid dysfunction go unrecognised, though sporadic cases of transient hypothyroidism are now being seen in Britain. Their clinical implications are uncertain; the condition is often self limiting, but it may herald later, more overt manifestations of thyroid disease. Certainly psychiatric disorders such as postpartum psychoses have been reported in some affected patients.'5 Systematic epidemiological studies of the prevalence of postpartum thyroid disease are now required in Britain and in Europe. If these show that postpartum thyroid disorders arise largely from the pool of asymptomatic women with thyroid antibodies then screening for such antibodies might be added to the routine tests performed in early pregnancy. Sensitive, robust, and automated assay systems for thyroid antibodies-for example, ELISA (enzyme linked immunosorbent assays)-are now readily available.2' Awareness of the risk to the fetus and neonate of transplacentally derived thyroid antibodies should now allow recognition and early treatment of the rare neonatal thyroid syndromes.