“What multivitamins do you avoid during the second trimester?”

Here are some general guidelines regarding multivitamins to avoid during the second trimester: Vitamin A (retinol): High doses of vitamin A can be harmful to the developing fetus.1 It's best to avoid supplements containing retinol and limit intake of foods high in vitamin A, such as liver and liver products.2 Iron: While iron is essential for both you and your baby, excessive iron intake can be harmful. If you're taking a prenatal vitamin that already contains iron, you may not need additional iron supplements. Vitamin K: While vitamin K is important for blood clotting, excessive intake can be harmful. Most prenatal vitamins contain adequate amounts of vitamin K, so additional supplementation is usually not necessary.