Every mother knows how important nutrition is in pregnancy; specifically taking folic acid and vitamin-D supplements to ensure their growing baby gets the best start. Yet few have given much thought to iodine; but they should – it boosts brain development in the womb, and iodine deficiency can cause learning disabilities in the child.

Now evidence is building that suggests many women in the UK are iodine deficient and that low levels during pregnancy may put the unborn child at risk. In response, iodine experts are calling for government recommendations that pregnant and breastfeeding women take iodine supplements to make up for the deficiency.

What can happen if someone is iodine deficient?

Iodine is essential for building a healthy brain, skeleton and metabolism. During the first 14-16 weeks of pregnancy, a foetus is entirely dependent on the mother for its supply of thyroid hormone. If she is deficient in iodine and thyroid hormone both during pregnancy and during pre-conception, the baby risks mental impairment. Severe iodine deficiency can lead to the extreme disability known as cretinism.

Are women in the UK iodine deficient?

Yes – mild to moderately so, but this is enough to put the foetus at serious risk of brain abnormalities and low IQ. Professor John Lazarus, Chair of the UK Iodine Group and a specialist in hormone disorders, points out that there have been at least five recent surveys of pregnant women living across the UK showing a substantial amount of iodine deficiency in the first trimester of pregnancy. In 2011, another study also showed that two-thirds of 15-year-old girls in the UK were iodine deficient. The concern is that many of these girls will go on to become mothers.