Iodine deficiency in pregnancy

Why is iodine in the news?

A study of 1,000 families showed lower IQs and reading scores in primary-school pupils whose mothers were iodine deficient during pregnancy.

Urine samples taken from pregnant women in south-west England showed that two-thirds had iodine deficiency.

The research is significant because it shows that even mild iodine deficiency in mothers affects their children's IQ.

Why do women of childbearing age, in particular, need iodine?

Iodine is a mineral that our bodies use to make hormones which are necessary for brain development in unborn and newborn babies, and growth and metabolic regulation throughout our lives.

Insufficient iodine if you're pregnant or breastfeeding may impede your baby's brain development in the womb and in their early months, and prevent them reaching their full potential. 

Iodine amountsHow much iodine do you need to eat?

  • Pregnant women: 250mcg per day
  • Breastfeeding women: 250mcg per day

This table from the British Dietetic Association shows the amount of iodine in different food portions.

But pregnant women need to follow health advice about foods to avoid during pregnancy.

Iodised salt (ie salt with added iodine) is available in some supermarkets, but don't increase the amount of salt you normally eat.

Which foods are rich in iodine?

Fish, milk and dairy products.

Who is at risk of iodine deficiency?

  • Vegans and vegetarians
  • Anyone who is allergic or intolerant to fish or dairy products

Who needs iodine supplements?

Most adults with a healthy balanced diet don't need iodine supplements. But if you have thyroid disease, you should speak to your GP about whether you need to take additional iodine.

Excess iodine is dangerous and doctors advise against seaweed or kelp supplements as an iodine source because the amount of iodine in supplements can vary considerably and can provide excessive amounts.

What about iodine supplements if you're pregnant or breastfeeding?

It can be difficult to get enough iodine from diet alone when you're pregnant or breastfeeding, particularly if you don't eat dairy or fish.

Iodine in milk

• Organic milk has a 40% lower iodine content than non-organic milk.

• Only some soya milks are fortified with iodine - check the label.

Many multivitamin and mineral pregnancy supplements contain iodine (check the label). If the supplement contains 150mcg of iodine, then you need 100mcg from your diet.

If you eat lots of fish and dairy already, you may not need a supplement. If you're in doubt about whether you're eating sufficicent iodine, talk to your GP.

And if you're not pregnant or breastfeeding, you still need to check you're getting enough iodine in your diet in case you have an unplanned pregnancy.

Last updated: about 3 years ago