No one does research giving herbs during pregnancy
so we don't know for sure.
It seems safe to use in cooking but taking medicinal amounts may cause bleeding or stimulate uterine contractions. I advise caution with all herbs in the first trimester. It is probably safest in the final weeks of pregnancy. See http://bit.Ly/16ma7p2 ; http://www.Nlm.Nih.Gov/medlineplus/druginfo/natural/662.Html.