We retrospectively collected data from 62 pregnant females who were followed for hyperthyroidism (n=17), hypothyroidism (n=21), euthyroid Hashimotos thyroiditis (n=9), and simple goitre and other non-autoimmune thyroid diseases (n=15).Among them 33 showed at least once during pregnancy low FT4, or low FT3 and FT4 in total on 74 occasions. Low FT4 was found on 15, low FT3 on 15 and low FT3 and FT4 on 44 occasions. Accompanying TSH was lowered on 23 and normal on 51 occasions. Changes spontaneously disappeared on 8 occasions, normalized after levothyroxine treatment on 10 occasions, persisted despite levothyroxine administration on 23 occasions and persisted without therapy on 18 occasions. On 15 occasions we were unable to follow the effect of therapy because patients came next time after delivery. We see that levothyroxine treatment normalized hormone levels on 10 occasions but failed to do so on 23 occasions. At the same time changes spontaneously disappeared on 8 occasions. Aforementioned changes of thyroid hormones fit in non-thyroidal illness pattern. Changes were observed during the whole pregnancy from 4th to 36th week of gestation. All children from these pregnancies were healthy and had so far normal development. Albeit maintenance of maternal euthyroidism during pregnancy, especially normal thyroxinemia, is of paramount importance for development of child, still there is a number of pregnant females in which this cannot be accomplished due to non-thyroidal changes, fortunately without any adverse effect on the foetus. It is important to stress that we live in iodine sufficient environment and that in all cases hypothyroidism was excluded. Changes appeared equally in patients receiving no therapy and in patients taking levothyroxine. Previously hyperthyroid patients showed these changes while being in remission.
24 - 28 Apr 2010
European Society of Endocrinology