I was drinking Raspberry Leaf tea from about 34 weeks....one cup and then 4-6 cups after 37 weeks. I had a very quick labour! Very quick but pretty painful though so I don't know if that is considered efficient. I dilated 7cm in 3 hours. VE at 4:45pm was 3cm, fully dilated and pushing at 7:40pm...baby born at 7:59pm