Herbalists often recommend that pregnant women drink raspberry leaf (Rubus idaeus) tea as a uterine tonic to promote shorter and easier labor. To determine its effectiveness, the Holistic Nurses Association of New South Wales, Australia, had nearly 200 women take two tablets (1.2 g each) daily from the time they were eight months pregnant until labor. Raspberry did not shorten the first stage of labor, but the second stage was almost ten minutes shorter compared to a control group. Women taking raspberry also had fewer forceps deliveries (19.3 percent versus 30.4 percent), and there were no adverse effects in the women or their babies.
Source: Simpson, M., et al. “Raspberry leaf in pregnancy: its safety and efficacy in labor.” Journal of Midwifery and Women’s Health 2001, 46(2): 51–59.