Maternal iodine status and the thyroid function of pregnant mothers and their neonates in Jaffna District of Sri Lanka

Abstract

Introduction:Iodine status of pregnant women and their newborns have not been studied in Jaffna District, Sri Lanka. This study was planned to assess the maternal iodine status and thyroid function at the third trimester of gestation and the thyrotrophin level of their neonate.Methods:Four hundred and seventy-seven pregnant women and their newborns were randomly selected among six Medical Officers of Health Divisions out of 12 in Jaffna District, Sri Lanka. Maternal thyroid stimulating hormone (TSH), free thyroxine (fT4), thyroglobulin (Tg), urinary iodine levels, and the neonatal thyrotrophin (nTSH) level were assessed.Results:In this study, mean age, weight, height, and gestational age of the mothers were 28.95 (±5.46) years, 63.02 (±11.56) kg, 154.39 (±6.00) cm, and 39.33 (±1.37) weeks, respectively. Maternal median urinary iodine concentration (UIC) was 140.0 μg/L (inter-quartile range 126.0–268.0 μg/L). Median values of the maternal serum TSH, fT4, and Tg were 1.9 mIU/L, 12.6 pmol/L, and 21.4 IU/L, respectively. Among the 477 newborns, 50.5% (n = 239) were males. Mean birth weight of newborn was 3.03 (±0.43) kg, while the mean length was 51.1 (±2.1) cm. Among the newborns, 18% (n = 86) had nTSH level > mIU/L and 37.7% (n = 180) within TSH level > mIU/L. nTSH level had positive but very weak correlations with maternal thyroid parameters, that is, UIC (r = 0.06, P = 0.13), fT4 (r = 0.01, P = 0.05), TSH (r = 0.09, P = 0.05), and Tg (r = 0.12, P = 0.03).Conclusion:On the basis of the World Health Organization criteria, the iodine status of pregnant women was inadequate in this region and also nTSH levels indicate moderate iodine deficiency during pregnancy. Therefore, the continuous education on adequate iodine intake during pregnancy and monitoring of iodine status are useful.

Iodine and Thyroid Function Status, and Anti-thyroid Peroxidase Antibody among Pregnant Women in Eastern Nepal

“…In a study in Sri Lanka, median thyroglobulin was 21.4 IU/L among pregnant women in 39.33 (±1.37) weeks of gestation. 17 In a study done in France,the median thyroglobulin in pregnant women was 16.2 μg/L, and it did not differ across trimesters, and was significantly higher than in the control group of non-pregnant adults (11.7 μg/L) {p=0.02}. 18 Because of the harmful consequences of iodine deficiency on mother and fetus health, it is recommended that pregnant women take extra iodine than normal adults.…”

“…18 Because of the harmful consequences of iodine deficiency on mother and fetus health, it is recommended that pregnant women take extra iodine than normal adults. 17 Universal salt iodization has been the most common strategy of eliminating iodine deficiency in landlocked countries, and this been successful in Nepal with increasing number of households consuming adequately iodized salt and median UIC among school children is rising. 1,19 Thyroid dysfunction has been observed as the most frequent endocrine disorder in pregnant women.…”

Non-iodized salt consumption among women of reproductive age in sub-Saharan Africa: a population-based study

“…Up to 65 % of pregnant women suffer from iodine deficiency in developing countries and this deficiency is associated with an increased risk of poor birth outcomes such as low birth weight, spontaneous abortions and congenital malformations. Children born to mothers with iodine deficiency are at risk of developing neurological deficits, cretinism and death (6)(7)(8)(9)(10) . In addition, iodine deficiency in women is responsible for goitre, a condition associated with stigmatization and poor quality of life (1,2,5,11,12) .…”

Establishment of National programme on newborn screening for congenital hypothyroidism

“…The appropriate age of sampling in the newborn screening programme was a matter of debate. The optimum age of sampling depends on many factors like the number of diseases screened for and screening method (9). However, screening before hospital discharge or before blood transfusion was preferable to avoid missing the diagnosis of hypothyroidism.…”