Iodine in pregnancy

Iodine is a key nutrient during pregnancy. For a start, it’s involved in many functions and processes of your body, including making your thyroid hormones. These hormones affect the way your cells function, which in turn affect many processes of your body, such as your heart rate and your metabolism. Having low levels of these hormones has been linked to weight gain, fatigue and mood swings.  

Iodine’s also vital for your baby’s brain development. During pregnancy, your baby’s cells rely on your iodine intake, including their rapidly developing brain cells². A good supply of iodine is essential to building this complex organ². A well-balanced pregnancy diet that includes a healthy intake of iodine-rich foods will support your baby’s developing brain, contributing to their learning and motor skills, and helping to set the stage for all future development.

Despite being present in many foods, studies have found that there’s a widespread lack of iodine in our diets³. Because the best sources are all animal-based, if you’re vegetarian, vegan or follow a plant-based diet, you may be at a higher risk of iodine deficiency³. If you’re concerned that you might not be getting enough iodine in your diet, talk to your midwife about taking a pregnancy-safe iodine supplement⁴.

The daily recommended amount for women is 140mcg. If you decide to breastfeed your baby, you shouldn’t need to make any special dietary changes but it’s a good idea to eat healthily. For more advice, you can always talk to your midwife or healthcare professional.

White fish and dairy foods are all excellent sources of iodine⁴. You can also increase your intake by replacing your regular salt with an iodised version (which is salt that has been fortified with iodine³). Although it goes without saying, you shouldn’t increase your salt intake in order to boost your iodine intake.

While seaweed (which absorbs iodine from seawater) can also be an excellent source, the amount of iodine in seaweed is highly variable. Some varieties contain very high levels of iodine, and could be harmful if eaten in large quantities on a regular basis. Some health bodies advise not eating seaweed more than once a week during pregnancy. However, small amounts of powdered or crumbled seaweed can be added to soups, stews and salads.

Learn about other foods to avoid during pregnancy.

It’s worth noting that the iodine content of dairy varies depending on the season, due to variations in how cows are fed throughout the year. Higher levels of iodine have been measured in milk over the winter when cows are fed on winter feed rations, compared with the summer, when lower levels have been measured⁵. These seasonal changes have been linked to the amount of iodine in maternal diets⁶.