The neonatal screening results of TSH and 17-hydroxyprogesterone (17-OHP) in 34 study neonates born to mothers exposed to AEDs during pregnancy and their matched controls were evaluated at the Department of Paediatrics, Karolinska Institute, Stockholm, Sweden. The AEDs were carbamazepine 17, phenytoin 10, and polytherapy in 7 patients. In the group as a whole, there were no significant differences in the TSH and 17-OHP values in patients and controls. In a separate analysis of 6 infants exposed to polytherapy of 2 or more AEDs, there was a non-significant tendency to lower TSH and 17-OHP. Thyroid and steroid screening values were not correlated with AED plasma concentrations measured 1 month before delivery. [1]

COMMENT. Carbamazepine and phenytoin induce metabolic enzymes and enhance metabolism of steroid and thyroid hormones. Low levels of thyroxine T4 and steroid hormones are reported in young adults treated with CBZ and PHT but not with valproate monotherapy. Serum T3 is unaffected by AEDs. (Prog Ped Neur I, 1991, ppl26-7). The above study suggests that CBZ and PHT monotherapy during pregnancy may not alter fetal thyroid and steroid metabolism.