Iodine deficiency in pregnant women living in the South - East of the UK : the influence of 1 diet and nutritional supplements on iodine status

21 Iodine is a key component of the thyroid hormones which are crucial for brain development. 22 Pregnant women are vulnerable to iodine deficiency because their requirement for iodine is 23 higher than that of non-pregnant adults. Data on the iodine status of UK pregnant women are 24 sparse and there are no such data in the South East. One hundred pregnant women were recruited 25 to a cross-sectional study at the Royal Surrey County Hospital, Guildford, at their first-trimester 26 visit for an ultrasound scan. Participants provided a spot-urine sample (for the measurement of 27 urinary iodine and creatinine concentrations) and 24-hour excretion of iodine was estimated from 28 the urinary iodine-to-creatinine ratio. Women completed a general questionnaire and a food-29 frequency questionnaire. The median urinary iodine concentration (85·3 µg/l) indicated that the 30 group was iodine deficient by WHO criteria. The median values of the iodine-to-creatinine ratio 31 (122·9 µg/g) and of the estimated 24-hr iodine excretion (151·2 µg/day) were also suggestive of 32 iodine deficiency. Urinary iodine concentration was significantly higher in women taking an 33 iodine-containing prenatal supplement (n=42) than in those not taking such a supplement 34 (P<0·001). In adjusted analyses, milk intake, maternal age and iodine-containing prenatal 35 supplement use were positively associated with estimated 24-hour urinary iodine excretion. Our 36 finding of iodine deficiency in these women gives cause for concern. We suggest that women of 37 childbearing age and pregnant women should be given advice on how to improve their iodine 38 status through dietary means. A national survey of iodine status in UK pregnant women is 39