This quoted from a worksheet on herbs that mw gave me:
"Red Raspberry: A MUST! Unequalled by any other, this herb works specifically on a woman's re-creative organs, stimulating, toning and regulating. Drink 1-3 cups each day, expecially in the last 6 weeks of pregnancy."
I've been drinking probably 4-5 cups a week (because some days I forget). Sometimes I make it with a bag of peppermint, too
Oh, and I just saw on the same worksheet under 'Pregnancy Formulas': Pregnancy Tea - equal parts Red Raspberry, comfrey and peppermint. I may need to get some comfrey.