You use an infusion of the leaf of Rubus idaeus to ease pregnancy and/or childbirth. The controversy is when to use it - throughout the pregnancy or just the last trimester. One piece of advice on the paracelsus list:
From: herbal.got.net (Roy Upton)
Almost all popular texts state that red raspberry is good to use throughout pregnancy. On several occasions I have seen first trimester women experience spotting each time they drank moderate amounts of the tea. When they discontinued the tea, spotting stopped. Four tried the tea again and spotting began again. I asked a few midwives about their experience and found that they too had experienced the same thing, so did not generally recommend it in the first trimester. I do not feel that red raspberry is inherently problematic, but also feel that is not necessarily inherently benign.