i remember i had this same questiosn when i was pregnant and unfortunately things like herbal teas are not often on the typical "do no eat" list for pregnant women. that said i would definitely ask your ob about this. although herbal teas are "natural" they are not regulated so you can never be sure what you are getting. plus there isn't much research to know for sure whether any specific ingredients are harmful. i remember i pretty much avoided them. here's some more information that may help: <link>
can you drink herbal teas while pregnant that contain echinacea eucalyptus and stevia? . other ingredients include peppermint licorice roasted chicory natural menthol extract(contains soy lecithin) lavender and chinese star anise