We recently made first page of Reddit because people were freaking out over some of the herbs in our fertility teas, which aren't meant for pregnancy. This felt like a perfect teaching opportunity to discuss why the herbs for fertility versus pregnancy are different.
Some woman showed concern about mugwort specifically, which is a well-known herb that can warm the womb to decrease the spasm and cramping that can contribute to miscarriage when there is cold in the womb. Because mugwort can increase heat, women who don't need mugwort might have an earlier period. Ariele discusses here the use of mugwort in her warming tea blends.