"Maternal/Neonatal" iodine status in patients with prolonged physiological jaundice

The increasing knowledge indicated that borderline hypothyroidism may cause neurodevelopmental disorders. Borderline compensated congenital hypothyroidism could caused by iodine deficiency or iodine overload. One of the most important etiological factors causing prolonged jaundice in the neonatal period is congenital hypothyroidism. Aimed of this study is to investigate the frequency of borderline or overt hypothyroidism in a group of newborn with prolonged physiological jaundice, and to evaluate iodine status of these babies and their mothers.

Fifty-five apparently healthy newborn were evaluated. Twenty-five of them showed borderline thyroid dysfunctions. Remained 30 babies had normal thyroid function, considered as euthyroid group. Iodine status was evaluated by measuring urinary iodine excretion.

According to UIE, maternal iodine deficiency (55%) associated with neonatal iodine overload (65%) had came to attention. Although mean urinary iodine levels in both mother groups were similar, the mean urinary levels of borderline hypothyroidic and euthyroid groups were 432+/-129 microg/l and 271.5+/-137 microg/l, respectively. Iodine overload was also presence in newborn with normal thyroid function tests.

We considered that individual sensitivity to iodine overload could make the differentiation on thyroid function. Iodine overload in important degree seen in borderline hypothyroidic babies emphasize the harmful effect of topical antiseptic iodine application that given to mothers during labor. This application could also mask possible prenatal iodine deficiency.