Urinary iodine levels and thyroid hormones in first trimester pregnant women in Nigeria

Abstract

Iodine is an essential component of thyroid hormones required for the normal growth, development and functioning of the body. Its deficiency causes intellectual impairment, reproductive risks such as overt hypothyroidism, infertility, gestational hypertension, increased first trimester abortions and still births. Paradoxically, iodine deficiency disorders (IDD) are among the easiest and cheapest preventable disorders. This study therefore evaluated dietary iodine status and some thyroid parameters in first trimester (1Oth-12th week) pregnant women Methods: Forty-two healthy pregnant women, mean age and gestational age of 30±5.22 years and 11.43±0.83 weeks respectively were recruited in consecutive manner for this study after obtaining their informed consents. Urinary iodine levels were analysed in casual urine samples using the ammonium persulphate method as described by Dunn et aI while thyroid stimulating hormone (TSH) and free thyroxine (fT4) were measured in serum using Enzyme Immunoassay technique. Results: 40.5% of the participants had adequate dietary iodine, 47.6% had more than adequate, 9.5% had mild iodine deficiency, while 2.4% had excess dietary iodine. 92.9% of the participants had normal TSH values, 4.8% and 2.4% fell in the hypothyroid and hyperthyroid ranges respectively. 91.4% of the participants had normal values for fT4, 8.6% had below normal while none had above. Qualitative salt analysis shows iodization of salt in all the salt samples tested. Conclusion: This study reveals adequate iodine nutrition in the first trimester sub-population, however, screening for overt and subclinical hypothyroidism should still be strongly considered.