[Thyroid disease]

The incidence of pregnant women with thyroid dysfunction has been reported to be around 0.1-0.4%. Graves' disease accounts for more than half of these disorders. The main cause of thyroid disease in pregnancy and puerperium is autoimmune dysfunction. Whether there may be goitre or exophthalmus present, clinical signs as inappropriate weight gain, high systolic pressure, palpitation (greater than or equal to 110/min), emotional lability, fatigue, acceleration of suppression of the Achilles' tendon reflex should induce changes in the biochemical thyroid function tests. Parameters for the diagnosis and management for hyperthyroidism are serum levels of free T4 and TSH, while those of T3, reverse T3, and TSH are for hypothyroidism. Serum anti-microsomal antibodies and anti-thyroglobulin antibodies which have no effect on the fetus are also good markers for severity. The transplacental transfer of maternal TSH receptor antibodies consisting of stimulatory and inhibitory immunoglobulins and maternal thyroid-binding inhibiting immunoglobulins play roles in the development of transient neonatal hyper- or hypothyroidism. Fetal control is achieved by optimal maternal management. Untreated hyperthyroidism may be associated with fetal malformations. This risk may be reduced by antithyroid drug treatment of up to 150 mg/day of propylthiouracil which has less chance of placental passage and less secretion into the mother's milk than methyl-mercapto-imidazol. Maternal thyroid function should be kept in the upper limit of normal range, taking into consideration the fetal dysfunction induced by over-administration of the drug which passes through placenta. Children of hypothyroid women taking inadequate replacement therapy manifested lower IQ values compared to the progeny of euthyroid or hypothyroid women taking adequate therapy.(ABSTRACT TRUNCATED AT 250 WORDS)