Is soy safe during pregnancy?

What does the evidence say about soy during pregnancy?

1. Soy use during pregnancy may be unsafe in amounts greater than those commonly found in foods, which places the caution on supplements rather than on tofu or edamame. 1
2. Soy supplements may contain isoflavones, compounds similar in structure to the hormone estrogen, and effects can vary across different soy products and different populations. 1
3. Little is known about whether soy is safe while breastfeeding in amounts greater than those commonly found in foods. 1
4. Soybeans appear among the food sources of potassium, and the recommended potassium intake rises to 2,900 mg a day during pregnancy. 2
5. Beans and peas are named among the natural folate sources, against a pregnancy target of 600 mcg DFE a day. 3

Is soy safe in each trimester?

• First trimester. Soy foods are often the thing that still appeals when meat and eggs have turned on you, and tofu is one of the blandest protein sources available. Nothing about the first trimester changes the guidance. The line stays where it always is: food yes, isoflavone capsules ask first.
• Second trimester. If you are eating plant-based, this is a good moment to look at the whole protein and nutrient picture with your clinician rather than at soy in isolation. Soybeans also contribute potassium, and beans and peas are on the folate list.
• Third trimester. Nothing new here for soy foods. If anyone hands you a soy isoflavone or red clover supplement for late-pregnancy symptoms, that is the moment to check, since NCCIH's caution is specifically about amounts beyond what food delivers.