Iodine for fertility

On this page

1. What is iodine?
2. Function and how it works
3. Fertility benefits
4. Recommended daily dose
5. Food sources
6. Cautions and contraindications
7. My Fertility Guide
8. Related pages

1. What is iodine?

Iodine is an essential trace element that is vital for the production of the thyroid hormones thyroxine (T4) and triiodothyronine (T3). Iodine deficiency is the most common cause of preventable mental retardation worldwide, and in newborns can cause cretinism. Vegetarians and vegans are at particular risk of iodine deficiency.

Reference ranges and recommended intakes vary from country to country — always interpret guidance against the recommendations of your own healthcare authority.

2. Function and how it works

Iodine supports fertility through:

1. Thyroid hormone production. The thyroid gland concentrates iodine and incorporates it into T4 and T3, which regulate metabolism, ovulation, the uterine lining and the maintenance of pregnancy.
2. Replacing menstrual losses. With iron, iodine helps replace what is lost during menstruation through its role in red blood cell production.
3. Fetal brain development. Iodine is critical for fetal brain and nervous system development, particularly during the first trimester.
4. Breast tissue health. Iodine is concentrated in breast tissue and supports its health throughout life.

3. Fertility benefits

For women with subclinical hypothyroidism, raised TSH or unexplained fertility difficulties, ensuring adequate iodine is part of supporting thyroid function. Iodine deficiency is one of the most common but easily corrected causes of thyroid-related infertility.

4. Recommended daily dose

I recommend a daily dose of 150 mcg of iodine for women trying to conceive, increasing to around 220–250 mcg during pregnancy and breastfeeding. Most prenatal supplements include iodine at this level.

5. Food sources

Good sources of iodine include:

1. Sea fish (cod, haddock, salmon, sardines)
2. Seaweed (kelp, nori, wakame, kombu) — particularly concentrated
3. Eggs
4. Unrefined sea salt
5. Dairy products (modest amounts)

Most refined table salts have iodine added, but the other 60+ trace elements have been stripped out. Use natural unrefined sea salt where possible. Vegans and vegetarians need to be particularly careful to include adequate iodine, often through small amounts of seaweed.

6. Cautions and contraindications

1. Excessive iodine intake (above 1,100 mcg per day) can paradoxically suppress thyroid function and worsen autoimmune thyroid disease.
2. Avoid very high-dose iodine kelp supplements without medical supervision.
3. People with Hashimoto's thyroiditis should discuss iodine supplementation with their doctor — the right dose can help, but excess can worsen the condition.
4. Always consult with a fertility specialist or your doctor before starting any new supplement regime.

7. My Fertility Guide

8. Related pages

• Fertility supplements directory
• Selenium — required for T4-to-T3 conversion
• Iron
• Zinc
• Thyroid stimulating hormone (TSH)
• Thyroxine (T4) and triiodothyronine (T3)