Essential oils that are contraindicated during pregnancy should be avoided throughout pregnancy and not just during the first semester. According to “Essential Oil Safety” by Robert Tissearnd and Rodney Young, essential oils that are contraindicated during pregnancy and lactation are: Anise, Birch, Black Seed, Buchu, Carrot Seed, Cassia, Cinnamon Bark, Chaste Tree, Cypress, Fennel, Dill, Feverfew, Ho Leaf, Hyssop, Lanyana, Spanish Lavender, Mugwort, Myrrh, Myrtle, Oregano, Parsley Leaf, Parsleyseed, Pennyroyal, Rue, Sage (Dalmatian and Spanish), Savin, Tansy, Thuja, Western Red Cedar, Wintergreen, Wormwood (all types) and Yarrow.
