Thyroid Profile of Term Appropriate for Gestational Age Neonates in Nigeria: A Forerunner to Screening for Congenital Hypothyroidism

Thyroid hormones in normal quantity are vital for physical growth and mental development during fetal and postnatal life. The available publications in Sub-Saharan Africa on the thyroid function of newborn infants was reported in babies delivered in moderate to severe goitre zones; utilizing the hormone levels from these studies may have a measure of bias. Newborn screening for congenital hypothyroidism (CH) in Sub-Saharan Africa is still a mirage, the technicality of the best timing for collection of blood samples need to be studied. Consequently, we report the serum levels of total thyroxine (T4), triiodothyronine (T3) and thyroid stimulating hormone (TSH) at birth and at 72 h after birth, and to ascertain if there is any significant difference between them. This was a prospective cross-sectional study (6 months period) between November and April 2005. One hundred and fourteen apparently healthy term AGA neonates had their thyroid function analyzed, the females (59) were slightly more in number than the (males 55). Most of them were between GA of 37-38 weeks at birth. The observed 72 h mean values of serum T3 and T4 (1.06 and 101.38 nmol l(-1)) compared with the cord values at birth (0.89 and 75.48 nmol l(-1)), was not statistically significant. The mean cord TSH levels (13.59 mU l(-1)) compared with 72 h serum TSH levels (10.25 mU l(-1)) was also insignificant p = 0.3. For Sub-Saharan Africa cord TSH analysis may be a reasonable choice for newborn screening for congenital hypothyroidism.