Neonatal chemical hypothyroidism in Nigeria

To investigate the level of neonatal chemical hypothyroidism (NCH), thyroid function was measured in the cord blood of 271 neonates in an area with a high prevalence of endemic goitre, Bassa (n = 140), and a nonendemic area, Jos (n = 131), in Plateau State, Nigeria. NCH was defined as T4 < 40 nmol/L and TSH > 49 mU/L and borderline compensated NCH as T4 31-50 nmol/L and TSH 41-49 mU/L. NCH was detected in 16.4% of neonates in Bassa and in 3.8% in Jos. Borderline compensated NCH was detected in an additional 18.6% in Bassa and 8.4% in Jos. Contamination of foodstuffs and water by iodine-containing antiseptics and disinfectants during the antenatal period, in addition to factors responsible for endemic goitre, e.g. iodine deficiency and goitrogens, are considered to be responsible for the high prevalence of NCH in the Bassa area. As most infants' thyroid function recovers with time, the former might be a more important factor in the aetiology of NCH.