| Autor: |
Kung, A. W. C., Lao, T. T., Chau, M. T., Tam, S. C. F., Low, L. C. K. |
| Předmět: |
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| Zdroj: |
Clinical Endocrinology; Dec2000, Vol. 53 Issue 6, p725-731, 7p |
| Abstrakt: |
Severe iodine deficiency disorders (IDDs) may have been eradicated in many parts of the world, but milder forms still exist and may escape detection. We evaluated the impact of pregnancy on the maternal and fetal thyroid axis in Hong Kong, a coastal city in southern China with borderline iodine intake. A prospective study performed in a maternity hospital. Two hundred and thirty pregnant women were prospectively studied and their neonates assessed at birth. Urine iodine concentration, thyroid function tests and thyroid volume (TV) by ultrasound were determined in the mothers during pregnancy and up to 3 months postpartum and in the neonates. Increased urinary iodine concentration was seen from first trimester onwards and the proportion of women having urine iodine concentration of < 0·4 µmol/l decreased from 11·3% in the first trimester to 4·7% in the third trimester. There was progressive reduction in circulating fT4 and fT3 concentrations and free thyroxine index (FTI) with increasing gestation and the percentage of women having subnormal levels at term were 53·2%, 61·1% and 4·8%, respectively. The serum TSH concentration during pregnancy doubled towards term. In the first trimester, multiparous women had significantly larger TV than the nulliparous women (P < 0·001). By the third trimester, TV had increased by 30% (range 3–230%) so that the goitre incidence was 14·1%, 21·8%, 25·9% during the three trimesters of pregnancy, and 24·3% and 21·9% at 6 weeks and 3 months postpartum (ANOVA, P < 0·05). The change in thyroid volume during pregnancy correlated positively with the change in thyroglobulin (r = 0·225, P < 0·002) and negatively with urinary iodine concentration (r = - 0·149, P < 0·02). Fourteen women with excessive thyroidal stimulation in the second trimester (defined as those with thyroglobulin (Tg) concentrations in the highest tertile and FTI in the... [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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