Iodine Deficiency - a Concern in Pregnancy

Pregnancy and Lactation a Time to Avoid Iodine Deficiency Disorders

Mar 15, 2009

Optimal iodine levels are necessary during pregnancy and lactation. Unfortunately iodine deficiency is occurring even in countries using iodized salt programs.

Iodine deficiency is a major health concern. The most vulnerable time for iodine deficiency is during pregnancy and lactation, and childhood. Unfortunately, worldwide these population groups are showing signs of potential iodine deficiency.

Iodine deficiency causes a range of conditions called “iodine deficiency disorders” (IDD). The result of iodine deficiency in pregnancy and lactation from the 2007 publication “Assessment of iodine deficiency disorders and monitoring their elimination” by the World Health Organisation (WHO) the United Nations Children's Fund (UNICEF), and the International Council for the Control of Iodine Deficiency Disorders (ICCIDD), is outlined below.

Iodine deficiency disorders in pregnancy and lactation, and childhood

“On a worldwide basis, iodine deficiency is the single most important preventable cause of brain damage. People living in areas affected by severe iodine deficiency may have an intelligence quotient (IQ) of up to 13.5 points below that of those from comparable communities in areas where there is no iodine deficiency.”

The iodine intake in the United States, along with numerous other countries, has been decreasing over the last decade, according to Purnendu K. Dasgupta et al, authors of “Iodine Nutrition: Iodine Content of Iodized Salt in the United States”, a study published in the 2008 Environmental Science & Technology journal, Volume 42, issue 4.

Iodine is required for the production of the thyroid hormones, thyroxine (T4) and triiodothyronine (T3). These thyroid hormones regulate growth, development, metabolism, and reproductive function in all age groups. Fetal and child development suffers the greatest impact from low levels of thyroid hormone and the greatest risk of iodine deficiency disorders.

During pregnancy, thyroid hormone production increases by 50 percent; this requires a greater intake of iodine to maintain thyroid function and thyroid hormone production.

At 11 weeks of pregnancy, the fetal thyroid gland begins to function and is producing its own thyroid hormone by 18 to 20 weeks. During this time, and up to the third year of life, iodine intake is crucial for the mother and child. In the developing fetus, the brain is rapidly growing and the nervous system developing. If iodine is unavailable or in short supply during pregnancy and lactation, there is a likelihood of irreversible brain damage and other iodine deficiency disorders.

Iodine Deficiency Prevalent in Pregnancy and Lactation

Evidence shows that even in countries with iodized salt or bread fortification programs, iodine levels in pregnancy and lactation may be deficient.

One study called “Iodine Deficiency in Pregnant Women Residing in an Area of Adequate Iodine Intake’’ was conducted in urban Rome in 2008 by E. Marchioni et al, and published in the Nutrition journal, volume 24 issue 5. Although Rome has had an iodized salt program in place since 2005, 92 percent of the pregnant women in this study had urinary iodine concentration (UIC) levels below adequate recommendations, compared to control subjects.

Supporting this result is a study conducted in Tasmania, by JR Burgess et al, “A Case for Universal Salt Iodization to Correct Iodine Deficiency in Pregnancy: Another Salutary Lesson from Tasmania” published in the 2007 Medical Journal of Australia journal volume 186, issue 11. Tasmania has had bread fortification with iodized salt in place since 2001, yet in the 517 pregnant women median UIC levels were at deficiency levels, with an increased risk of iodine deficiency disorders.

Iodine Supplement in Pregnancy and Lactation

The WHO, in the 2007 publication stated earlier in this article, recommends an iodine supplement to be taken by pregnant women and children in countries where less than 90% of the households are using iodized salt and the median UIC in schoolchildren is less than 100mcg/L. It is estimated 70% of households throughout the world have access to, and use, iodized salt. However, this does not take into account the variability of the iodine content of the salt.

Pregnancy and lactation requires daily intake of iodine rich foods along with an iodine supplement to increase the iodine intake to the recommended daily intake of 250 micrograms per day and reduce the risk of iodine deficiency disorders.

References

Patrick, L. (2008). Iodine: deficiency and therapeutic considerations. Altern Med Rev, 13(2), 116-127.

World Health Organisation (WHO), United Nations Children's Fund (UNICEF), & International Council for the Control of Iodine Deficiency Disorders (ICCIDD). (2007). Assessment of iodine deficiency disorders and monitoring their elimination: a guide for programme managers, 3rd ed.

The copyright of the article Iodine Deficiency - a Concern in Pregnancy in Vitamins & Minerals is owned by Melissa Peterson. Permission to republish Iodine Deficiency - a Concern in Pregnancy in print or online must be granted by the author in writing.