# Iodine in the second trimester

Source: https://www.pregnancypowerhour.com/nutrition/iodine-trimester-2
Last updated: 2026-07-01

> In the second trimester, adequate iodine intake remains crucial for your baby's ongoing brain development and thyroid function, building on the foundation laid in early pregnancy.

As you move into the second trimester, the role of iodine continues to be profoundly important, specifically for the critical development of your baby's brain and nervous system. During this period, your baby's thyroid gland is actively developing and beginning to produce its own hormones, which are essential for growth and neurological function. Iodine is a key component of these thyroid hormones, making consistent intake vital for supporting this intricate process.

It's worth noting that mild iodine deficiency is quite widespread globally, including in pregnant populations in the US and UK. The World Health Organization (WHO) highlights iodine deficiency in pregnancy as the leading preventable cause of intellectual disability worldwide. This underscores the importance of being mindful of your intake, even if you feel generally well. While the US Institute of Medicine (IOM) recommends 220 mcg/day for pregnant individuals, the WHO suggests a slightly higher intake of 250 mcg/day, reflecting a global consensus on its significance.

Meeting your iodine needs primarily through a food-first approach is a gentle and effective strategy. Common sources include iodized table salt, dairy products, seafood, and certain types of seaweed. When selecting salt, it's helpful to remember that many specialty salts, like sea salt and kosher salt, are typically not iodized, so checking labels can provide clarity. For other essential minerals in this trimester, you might also consider exploring information on [Iron in the second trimester](/nutrition/iron-trimester-2) or [Calcium in the second trimester](/nutrition/calcium-trimester-2), as they each play distinct roles in your evolving pregnancy.

Many prenatal vitamins include around 150 mcg of iodine, which can be a helpful contribution. The goal is to reach the recommended total intake through a combination of your diet and supplements. However, it's also important to be aware that excessive iodine intake, particularly above 1100 mcg/day, can lead to thyroid problems. This is especially relevant with some kelp supplements, which can contain very high and variable amounts of iodine. A balanced approach, ensuring adequate but not excessive intake, supports both your and your baby's health. The success of universal salt iodization globally stands as a testament to the powerful public health impact of ensuring this nutrient is accessible.

Understanding these nuances allows you to make informed decisions about your nutritional choices, fostering a sense of calm and confidence throughout your second trimester. Just as with [Iron in the first trimester](/nutrition/iron-trimester-1), early attention to nutrient intake sets a strong foundation for the months ahead.