Mustard greens contain oxalic acid, a naturally-occurring substance found in some vegetables, that leads to kidney stones. Besides, the leaves contain goitrogens that may interfere with thyroid hormone production and can cause thyroxin hormone deficiency in women with thyroid dysfunction. However, there isn’t much information available on the effect of having it during pregnancy and in some cultures, mustard greens continue to be part of people’s diet, even when a woman is pregnant.
