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Conception Pregnancy Jun 17, 2019
5 Minutes

Iodine: why it matters for conception and your baby’s brain…

We know neurodevelopmental issues including ADHD are on the rise in babies and children. We also know that in many cases it is taking us longer to get pregnant in the first place. One of the (many) potential drivers behind this is low Iodine – something many of us are deficient in without even realising. This article looks at why Iodine is so crucial, what happens if we don’t get enough, and most importantly how we can make a change and get enough to support our bodies and hormones.

Iodine: what is it and why is it so important?

It is a mineral, which sounds simple enough, but, it is crucial for thyroid function and the thyroid is central to conception, pregnancy and early years. Particularly when it comes to brain development. Why does it matter so much? Well, Iodine plays an important role because the thyroid uses iodine to make two very important hormones: T3 and T4.

Why are T3 and T4 so important?

These two hormones (in various forms) are responsible for things like cell division, growth/development and ovulation – pretty important for our purposes! They are also responsible for things like metabolism, repair, immune system function, our mental state and weight management. All things that have knock on effects to conception, pregnancy and early years of a child’s life. (1)

So, how much do we need?

Interestingly, a woman’s iodine requirements increase substantially during pregnancy (from 150 to 250 µg/day) to ensure adequate supplies are given to the fetus. (2)

Where do we get it from?

The trouble is that most food sources are relatively low in iodine and may not be enough to meet daily requirements. This is why in many countries we now have salt fortified with iodine. This has been one of the most successful nutritional interventions and now as many as 70% of the world’s households have access to iodised salt. (3)

How can having low Iodine affect conception?

New research has suggested that iodine has an important impact on fertility and in particular time to conception. Results from a recent population-based prospective cohort suggested that moderate to severe iodine deficiency is associated with a decrease in the probability of becoming pregnant within a given timeframe. The study looked at 467 American women who were trying to become pregnant.

The results? Women with moderate to severe iodine deficiency showed a 46% decrease in the likelihood of conception compared with women with normal iodine levels. (6)

How can having low Iodine affect Pregnancy and brain development?

Research has shown that moderate-to-severe iodine deficiency during pregnancy increases the rate of spontaneous abortion, reduces birth weight and increases infant mortality (5).

In fact, it has been shown to play an important role in preparing the baby for life outside the womb. Studies have shown that from mid gestation (around 24-28 weeks) various forms of these two crucial hormones (T3 and T4 alongside TSH which is the thyroid stimulating hormone) begin to rise. At birth there is a sudden release of all three hormones and this is believed to help the baby adjust to life outside the womb. (4)

Why does it matter so much for the healthy development of a baby’s brain?

Iodine not only matters for a foetus, but for young children too.

Simply put: when you have an inadequate thyroid hormone as a result of too little iodine, it will impact neurodevelopment. It does this by impacting factors that start to happen in the second half of the first trimester of pregnancy (cell myelination/migration/differentiation and maturation) in the fetal brain.

Not having enough can result in reduced verbal IQ, reduced fine motor skills, verbal abilities. It has also been linked to behavioural issues and increased incidence of ADHD. (8, 9, 10).

Can this be rectified?

Interestingly: correction of mild-to-moderate iodine deficiency in primary school aged children improves cognitive and motor function although the results are not clear on the impact if the iodine deficiency happens during pregnancy. (5)

Finally – and most crucially – what can I do to reduce my risk of iodine deficiency?

There are a few things to bear in mind: to start with – the avoids:

Firstly: the old enemy pesticides and specifically Glyphosate. Click here for much more detail, but, one of the leading experts in how Glyphosate impacts developing children (Stephanie Seneff at MIT et al) argues that there is significant evidence showing that Glyphosate impacts (lowers) maternal production of Thyroid Stimulating Hormone. So avoid as much as you can – click here for some easy tips and tricks to help with this. (14)

Secondly: Bromine: has been found to block iodine rich foods from being useful and absorbed to some extent. Where do you find Bromine? It is found in some industrially processed and packaged foods – yet another reason to avoid and to make your own!

Where can I find more iodine?

Well – food is not generally high in iodine, that being said there are some foods which have a higher concentration than others:

  • Sea Vegetables: think Kelp/Seaweed

  • Cranberries

  • Plain Yogurt

  • Strawberries

  • Potato

  • Seafood (although remember to go low down the food chain to avoid mercury)

  • Eggs

  • Green Peas

  • Cheese

  • Wild Caught Cod

  • Bananas

Of course we now have iodised salt – but – against this is the need to keep salt intake at a minimum during pregnancy and breastfeeding. In Europe, it is recommended that multivitamins are given to pregnant and breastfeeding mothers to reach the 250 microgram requirement. It is worth checking if your pregnancy/breastfeeding supplement has the required amount. If not and if in doubt discuss with your doctor.

Some signs to watch for and speak to your doctor about if you’re concerned you’re not getting enough:

These are signs that your thyroid is not working as it should: Hypothyroidism – which may be a sign that you do not have enough Iodine:

  • Heightened sensitivity to cold

  • Fatigue

  • Constipation

  • Depression/Irritability

  • Weight gain/trouble losing weight

  • Coarse, dry hair

  • Hair loss

  • Muscle cramp

  • Memory loss

  • Abnormal cycles

Of course the above could be a sign of many things, but if in doubt speak to your doctor and ideally get any thyroid issues addressed before conception.

All in all: conception, pregnancy and early years is the time that is most crucial to have our bodies in balanced and working order. If you are concerned that you are not getting what you need from your diet your first port of call is to speak to your doctor and get a comprehensive blood test – that way there is no guesswork and you know what you’re dealing with. After all, forewarned is forearmed and much better than wildly taking supplements that may not be necessary.


1. Micronutrient facts. CDC website.


3. World Health Organisation. United Nations Children’s Fund & International Council for the Control of Iodine Deficiency Disorders, Assessment of iodine deficiency disorders and monitoring their elimination. A guide for programme managers. 3rd edn. Geneva, 2007.


5. Zimmermann MB. The role of iodine in human growth and development. Semin Cell Dev Biol. 2011; 22(6):645-52.

6. Mills JL, Buck Louis GM, Kannan K, Weck J, Wan Y, Maisog J, Giannakou A, Wu Q, Sundaram R. Delayed conception in women with low-urinary iodine concentrations: a population-based prospective cohort study. Hum Reprod. 2018;33(3):426-433. doi: 10.1093/humrep/dex379.

7. Skeaff SA. Iodine Deficiency in Pregnancy: The Effect on Neurodevelopment in the Child. Nutrients 2011; 3(2): 265–273.

8. Velasco I, Bath SC, Rayman MP. Iodine as Essential Nutrient during the First 1000 Days of Life. Nutrients 2018, 10, 290; doi:10.3390/nu10030290

9. Bath SC, Steer CD, Golding J, et al. Effect of inadequate iodine status in UK pregnant women on cognitive outcomes in their children: results from the Avon Longitudinal Study of Parents and Children (ALSPAC). Lancet 2013;382:331–7.

10. Abel MH, Caspersen IH, Meltzer HM, et al. Suboptimal maternal iodine intake is associated with impaired child neurodevelopment at 3 years of age in the Norwegian mother and child cohort study. J Nutr 2017;147:1314–24.

11. Manousou S, Johansson B, Chmielewska A, et al. Role of iodine-containing multivitamins during pregnancy for children’s brain function: protocol of an ongoing randomised controlled trial: the SWIDDICH study. BMJ Open 2018;8:e019945. doi:10.1136/bmjopen-2017-019945


13. Glinoer D. The importance of iodine nutrition during pregnancy. Public Health Nutr. 2007 Dec;10(12A):1542-6. doi: 10.1017/S1368980007360886.

14. Samsel A, Seneff S: Glyphosate,. Pathways to modern diseases III: Manganese, neurological diseases and associated pathologies. Surgical Neurology International: 2015: 6:45


This article is for informational purposes only. This article is not, nor is it intended to be, a substitute for professional medical advice, diagnosis, or treatment and should never be relied upon for specific medical advice. The information on this website has been developed following years of personal research and from referenced and sourced medical research. Before making any changes we strongly recommend you consult a healthcare professional before you begin.

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