Normative thyroid-stimulating hormone values for healthy nigerian newborns

Background: Congenital hypothyroidism is a common congenital endocrine disorder prevailing all over the world. No nationwide screening exists for any sub-Saharan country. We present normative cord and capillary thyroid-stimulating hormone (TSH) values for healthy Nigerian newborns. Subjects and Methods: A cross-sectional study was carried out in 6 university hospitals in Nigeria between January 1 and December 31, 2013. Cord and heel blood placed on 4 concentric circles on a Whartman filter paper were analysed for TSH within 1 week of collection using AutoDelfia 1235 immunoassay (Perkin Elmer Wallace, Boston, Mass., USA) at Charité - Universitätsmedizin Berlin, Berlin, Germany. The mean TSH levels of the newborns were determined, considering their sex, birthweight, socioeconomic status, and birth city. The association between the mean TSH level and other parameters was determined by analysis of variance. Results: A total of 2,014 subjects were recruited during the study period. The mean TSH value for the subjects was 1.86 μIU/ml, and 98.1% of the newborns were within the 2.5th and 97.5th percentiles (range: 0.09-7.90 μIU/ml) of the TSH levels. We collected 247 cord and 1,767 heel samples, respectively, and the range was slightly higher in samples from cord blood. Conclusion: The study highlights the normal reference values for capillary/cord TSH levels in term Nigerian newborns. TSH was higher in one region, attributable to earlier sampling, but was not influenced by gender, socioeconomic status, or birthweight.