In the first ever report on the use of supplements containing iodine by pregnant women in Western Australia, researchers found a considerable discrepancy between recommendations that all women who are considering pregnancy, pregnant, or breastfeeding take a daily iodine supplement of 150µg, and actual intake levels.
The study, published in the journal ANZJOG, found that only 24% follow the guidelines prior to pregnancy, increasing to 66% after conception.
The data came from a cross-sectional study conducted on 425 pregnant women attending antenatal clinics in Perth.
"Iodine-containing supplements were reported as being used over the previous two months by 66% of participants compared to 24% in the year prior to pregnancy," wrote the researchers.
"The iodine content of the supplements used by the dose sub-group ranged from 38 to 500µg per daily dose, with a median (IQR) of 220 (150 to 220) µg. Seventeen women (18%) reported use of a dose containing less iodine than the NHMRC recommendation of 150µg."
Lack of understanding
When asked to select health problems associated with insufficient iodine intake, 56% of participants said they did not know.
Iodine is required for the production of thyroid hormones, which play a pivotal role in the early development of the central nervous system and most organs during gestation, infancy and childhood. Pregnancy also induces physiological changes which, in turn, generate a greater demand for iodine.
The study also found there was less likelihood of iodine supplementation among women on their second or subsequent pregnancies.
"The reasons for less use after the first pregnancy may be similar to those reported from focus groups in relation to folic acid supplements, namely, the added demands of employment or parenting on women in subsequent pregnancies, as well as lower perceived risk of poor foetal health outcomes if there has been no family history of these," stated the paper.
"Targeted efforts to reach those who have already given birth, through pharmacies, child health clinics, play groups, and parenting magazines or blogs, may provide improvement in uptake of the recommendation," they added, noting that based on mean urinary iodine levels of schoolchildren, Western Australia has been considered iodine-insufficient since 2006.
"Iodine-containing supplement use by pregnant women attending antenatal clinics in Western Australia"
Authors: Tammy Hine, et al.