IodineNutrition library
Iodine
The raw material for thyroid hormone, which drives fetal brain development — among the most consequential nutrients for neurodevelopment if deficient.
Trimester focus
| Stage | For the mother | For the baby |
|---|---|---|
| First trimester | Maternal thyroid output must rise ~50% to supply both mother and embryo. | Entirely dependent on maternal thyroid hormone before its own thyroid forms (~week 12). |
| Second trimester | Maternal needs stay elevated as the fetal thyroid begins functioning. | The fetal thyroid starts producing its own hormone, still needing maternal iodine as substrate. |
| Third trimester | Continues supplying iodine for sustained thyroid output. | Thyroid hormone continues driving the brain-growth spurt. |
Target note
Dairy, yolk, oysters. Yolk iodine swings widely.