Iodine in Pregnancy mcg per day

Iodine Requirements During Pregnancy and Lactation

Iodine is a trace mineral the body needs to build the thyroid hormones T3 (triiodothyronine) and T4 (thyroxine). Those hormones run your metabolism, and they also drive the developing baby's neurological growth. That is why the World Health Organization (WHO) puts the pregnancy target at 220 mcg/day, well above the 150 mcg/day set for non-pregnant adults. During lactation it climbs again, to 290 mcg/day, since a share of the mother's iodine ends up in breast milk.

When a mother runs short on iodine in pregnancy, the consequences are serious. It remains the leading preventable cause of intellectual disability worldwide, and in its severe form it was tied to congenital cretinism (profound mental retardation, deaf-mutism and stunted growth). Even a mild or moderate shortfall can hold back a baby's cognitive development. Brazil has required iodized salt since Federal Law 6.150/1974, a measure that all but wiped out endemic goiter; ANVISA has revised the permitted iodine content from time to time.

Applications

Obstetricians, endocrinologists, nutritionists and prenatal teams use this to check whether a diet supplies enough iodine. Some women carry more risk than others: those on salt-restricted diets (hypertension, preeclampsia risk), vegans, vegetarians who skip dairy and seafood, or anyone who has switched to non-iodized specialty salts like Himalayan or fleur de sel. They often need a supplement of 150–200 mcg/day of potassium iodide, which is usually built into prenatal vitamins.

FAQ

Why does pregnancy increase iodine needs by ~50%? Three things pile up at once. The mother's thyroid hormone output rises by about half, the kidneys clear more iodine, and from roughly week 12 the fetus draws iodine across the placenta to make its own hormones.

Can excessive iodine be harmful? It can. Taking more than 500–1100 mcg/day may trigger thyroid dysfunction (the Wolff-Chaikoff effect) in susceptible women. Steer clear of kelp and seaweed supplements unless a doctor is overseeing it.

Is this calculator a substitute for medical advice? No. For a prenatal nutrition plan tailored to you, talk to an obstetrician or endocrinologist, all the more so if you have thyroid disease or stick to a restrictive diet.