• Limit your exposure to mercury by not eating bigeye tuna, king mackerel, marlin, orange roughy, shark, swordfish, or tilefish. Limit eating white (albacore) tuna to 6 ounces a week. You do not have to avoid all fish during pregnancy. In fact, fish and shellfish are nutritious foods with vital nutrients for a pregnant woman and her fetus. Be sure to eat at least 8–12 ounces of low-mercury fish and shellfish per week.
• Avoid exposure to lead. Lead can be found in old paint, construction materials, alternative medicines, and items made in foreign countries, such as jewelry and pottery.
• Avoid taking high levels of vitamin A. Very high levels of vitamin A have been linked to severe birth defects. You should consume no more than 10,000 international units of vitamin A a day.
• Women who are obese (defined as having a body mass index [BMI] of 30 or greater) when they get pregnant have an increased risk of having babies with certain birth defects than women who are a normal weight. Among the most common obesity-related birth defects are NTDs, heart defects, and cleft palate. If you are planning a pregnancy, the best way to prevent problems caused by obesity is to be at a normal weight before you get pregnant.”

American College of Obstetricians and Gynecologists ACOG

(https://www.acog.org/womens-health/faqs/reducing-risks-of-birth-defects)