Maternal iodine status and neonatal thyroid-stimulating hormone concentration: a community survey in Songkhla, southern Thailand

Abstract

Objective: To determine iodine intake and urinary iodine excretion (UIE) in a group of pregnant Thai women and the concentration of thyroid-stimulating hormone (TSH) in their neonates. Design: A prospective cohort study. Setting: Three districts of Songkhla, southern Thailand. Subjects: Two hundred and thirty-six pregnant women. Results: A quarter of the participants lacked knowledge of iodine and the prevention of iodine deficiency, although 70 % used iodized salt. Those who did not use iodized salt stated that they had no knowledge about iodine (57 %) and no iodized salt was sold in their village (36 %). The median iodine intake in the three districts was 205-240 mg/d, with 53-74 % of pregnant women having iodine intake ,250 mg/d. The median UIE in the three districts was 51-106 mg/l, with 24-35 % having UIE , 50 mg/l. The mean neonatal TSH was 2?40 (SD 1?56) mU/l, with 8?9 % of neonates having TSH . 5 mU/l. Conclusions: The studied women and their fetuses were at risk of mild iodine deficiency. About a quarter of the participants lacked knowledge of the importance of iodine. Education regarding the importance of iodine supplements and the promotion of iodized salt should be added to national health-care policies in order to prevent iodine-deficiency disorders, diseases that are subclinical but have long-term sequelae. Keywords Iodine deficiency Neonatal thyroid-stimulating hormoneNeonatal TSH screening Urinary iodine excretionIodine-deficiency disorders (IDD) are a global public health problem (1)(2)(3) . Data from the WHO Regional Office for South-East Asia (SEARO) in 2004 showed that 600 million people worldwide were at risk of IDD and 172 million people were affected with goitre (4) . Nearly 20 million children born each year in this region are at some risk of mental impairment due to hypothyroidism in the mother and/or the fetus (4,5) . The three main indicators currently used for IDD monitoring to indicate iodine sufficiency are: (i) median urinary iodine excretion (UIE) .100 mg/l, with ,20 % of the population having UIE , 50 mg/l; (ii) enlarged thyroid gland by palpation or ultrasonography (goitre) present in ,5 % of the population; and (iii) thyroid-stimulating hormone (TSH) .5 mU/l in ,3 % of neonates (1)(2)(3) . Thailand is one of the countries in South-East Asia where IDD is endemic (4,6) . In 1989, the 'National IDD Control Project' on household and industrial salt iodization was established as a strategy for IDD elimination. However, a survey in 1997 in the north and north-east, the major endemic areas of IDD in Thailand, found that the prevalence of goitre in schoolchildren was still as high as 20-30 % and the prevalence of neonatal TSH concentration .5 mU/l was 30-50 % (7,8) . In southern Thailand, a coastal region, IDD was less prevalent as indicated by the 3-5 % goitre prevalence in schoolchildren and the higher levels of UIE (9) . However, a recent 2004 study indicated the prevalence of neonatal TSH . 5 mU/l in the fourteen provinces of southern Thailand to be 10-30 % (10) , indicatin...

Weight gain of mother, birth weight of infant and maternal knowledge regarding nutrition in Sri Lanka

“…In this study only 50% of the study population who have a weight gain within the accepted range 11-16 kg) had given birth to infants whose birth weight was within the normal range (2500≤3500) (9). Only 30% of the study sample having a good knowledge on nutrition has given birth to infants whose birth weight was within the accepted range (2500≤3500 kg) although no significant difference was observed between knowledge on nutrition & infant birth weight in the present study.…”

Transient Congenital Hypothyroidism in Turkey: An Analysis on Frequency and Natural Course

“…Some experts have proposed that the data on neonatal TSH screening for monitoring population iodine deficiency should be interpreted with caution due to technical issues including the time of sampling after birth (38). Nevertheless, many studies have shown an inverse relationship between neonatal TSH and maternal urinary iodine concentration, supporting the notion that the frequency of neonatal TSH concentrations >5 µU/mL was a sensitive indicator of iodine nutrition during pregnancy (39,40,41). In recent years, several studies have already demonstrated insufficient iodine intake of pregnant women living in different regions of Turkey (17,18), including apparently iodine-sufficient areas (19).…”

Thyroid Dysfunction during Late Gestation Is Associated with Excessive Iodine Intake in Pregnant Women

“…However, a proper balance of iodine intake is needed during pregnancy for the mother and the developing fetus. Studies have demonstrated that iodine deficiency during pregnancy may lead to maternal hypothyroidism (13) and impaired physical and intellectual development (14). Thus, many countries and institutions such as the World Health Organization (WHO) and the Food and Agriculture Organization (FAO) have established that the recommended nutrient intake of iodine for pregnant women should be at least 250 g/d (6,15).…”

“…In Haixing, pregnant women had higher serum concentrations of sTSH (2.89 vs. 2.19 mIU/liter; Z ϭ3.283; P ϭ 0.001) and FT 3 (4.03 vs. 3.78 pmol/liter; t ϭ 3.572; P Ͻ 0.001), and lower concentrations of FT 4 (13.35 vs. 13.77 pmol/liter; t ϭ Ϫ2.048; P ϭ 0.041) than pregnant women from Tianjin (Table 2). There were no significant differences in the positive rates of TPOAb and TgAb in pregnant women between Haixing and Tianjin (16.2 vs. 24.1% for TPOAb and 7.1 vs. 3.4% for TgAb; P Ͼ 0.05; Table 2).…”