I think that would be fine. I have had sleepy time tea with my daughter and she was and is fine. But if you plan on breatsfeeding peppermint isn't good for the milk, drys you out.
I heard herbal teas are good for pregnancy depending on what kind you use.
Is lipton green tea fine?
I didnt know that about it drying you out...good to know. With green tea i do believe they said it was okay and you could add honey to it even.
Because pregnancy I would drink at least 4 green teas a day. I love the stuff! Now I'm pregnant I have cut any caffeine drinks down to 2 a day max as I like my black tea strong and coffee strong. I couldn't however give up my green tea completely. Only time I managed to do that was when my HG was in full effect and I vomited everything including water. There are some herbal teas they don't recommend in pregnancy particularly first trimester such as nettle tea, but green tea in moderation is fine according to studies.