[Local Data] A local report on iodine status of pregnant women during early gestation

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General Medicine General Nutrition Obstetrics / Gynaecology Healthy Eating & Hydration
[Local Data] A local report on iodine status of pregnant women during early gestation

The article was to report iodine status of pregnant women during early gestation at a local obstetric unit.

The World Health Organization (WHO) considers iodine deficiency the single most important preventable cause of brain damage worldwide.


  • A local population survey conducted by the Centre for Food Safety during 2005 to 2007 indicated that only 5% adults had an iodine dietary intake within the safe range, but clinical and biochemical data was missing
  • Pregnant women have increased iodine requirement and iodine deficiency during early pregnancy has been shown to be associated with undesirable cognitive development in early childhood
  • The study aims to report the iodine status among local pregnant women at a local obstetric unit


  • Between July 2014 and November 2015, healthy pregnant women with no history of hyperemesis gravidarum were enrolled
  • Morning urine from ALL women was collected for measurement of iodine and creatinine levels
  • Daily dietary intake of iodine was measured  in a subgroup of women via structured interview using a standard food frequency questionnaire

Key Findings:

  • 600 pregnant women were enrolled (median of 7.0 weeks of gestation)
  • 71.5% women (429 out of 600) were iodine deficient according to the WHO definition, urinary iodine concentration (UIC) < 150 mcg/L
  • In the subgroup of women (n  = 146):
    • The median (IQR) daily dietary intake of iodine was 69.5 (47.3 – 152.4) mcg
    • Food sources of iodine:
      • Seaweeds, consumed by 76% of women, were the greatest source of iodine
      • Non-alcoholic beverages like soy milk, soup, soft drinks and water were the next most common source of iodine, contributing 21.5% of daily iodine intake
      • Only 4 out of 146 women consumed iodized salts regularly
  • At the time of enrollment, nutritional supplementation was reported by 69.0% women (414 out of 600), but only 39.4% (163 out of 414) of the supplements had iodine
  • In multivariate regression analyses, pregnant women recruited at a later gestational stage had a significantly higher UIC and were more likely to have started consuming a supplement with iodine


  • Local pregnant women are borderline iodine-deficient and have an inadequate iodine intake during early pregnancy
  • It is needed to educate the general public and to recommend women of childbearing age to have sufficient iodine intake before pregnancy




Tam WH, Chan RS, Chan MH, Yuen LY, Li L, Sea MM, Woo J. Moderate iodine deficiency among pregnant women in Hong Kong: revisit the problem after two decades. Hong Kong Med J. 2017;23(6):586-93.
Link to full article: http://www.hkmj.org/abstracts/v23n6/586.htm