Thyroid status during pregnancy and post partum in regions of iodine deficiency and endemic goiter.

During pregnancy the thyroid is subjected to increased demands which is associated with a tendency to endogenous iodine deficiency. Under the conditions of insufficient iodine supply in the GDR the pathophysiological changes result in: 1. prevalence of goiter in about 60% of pregnant women; 2. enlargement of the extent of neck in more than 50% of all pregnant women examined only returning to the prepregnant status in 25%-40%; 3. prevalence of goiter in newborn with 5%; 12.8% of 1948 stilborn had macroscopically an enlarged thyroid gland, the highest weight being 45 g. More than 53% of the stilborn examined by autopsy had a thyroid weight of over 3 g; 4. in contrast to the regions with sufficient iodine supply renal iodine excretion was steadily decreasing during pregnancy and post partum, changing the iodine deficiency from grade II to grade III; 5. low iodine excretion in newborn: 1.3 +/- 0.2 microgram I/day in goitrous (1.2 +/- 0.2 nmol I/mmol creatinine) 2.2 +/- 0.4 micrograms I/day in non-goitrous (2.0 +/- 0.4 nmol I/mmol creatinine); 6. according to ETR more than 50% of the pregnant examined showed a hypothyroid tendency. The pathophysiological changes during pregnancy caused by insufficient iodine supply can be met efficiently by careful thyroid hormone treatment or by the administration of 150 micrograms I daily. A mandatory iodine salt prophylaxis is demanded.