Using Raspberry Leaf Tea during Pregnancy

Can you give me more information on using raspberry leaf tea in the last few weeks of pregnancy to aid in labour?

In "The Natural Pregnancy Book" by Aviva Jill Romm (publishers The Crossing Press, Freedom, California), Aviva, a professional midwife and herbalist, says: "Rich in vitamins and minerals as well as a substance known as fragarine, which tones the uterine muscles, this herb is said to nourish the muscles, tonify the uterus and prevent hemorrhage due to both its high iron content and astringent qualities." It is one of the main ingredients of a nourishment tea that Aviva recommends be taken regularly throughout pregnancy, or it can be taken as a tea, by steeping 2 tablespoons of the dried herb per cup of boiling water for 20 minutes.
Amanda McQuade Crawford, in "Herbal Remedies for Women" (Prima Publishing), suggests that Raspberry leaf tea, taken during labour, helps to expel the placenta.
Anne McIntyre, in "The Complete Woman's Herbal" (Henry Holt publisher) suggests taking one cup daily of Raspberry leaf tea daily from the third month of pregnancy, 3 cups a day from the sixth month of pregnancy, one cupful an hour after contractions have begun, then "Once the digestive system shuts down, sips of the tea, or a few drops on the tongue taken as often as possible will be helpful". Anne states that Raspberry leaf is used after birth "to stimulate milk production and to speed recovery from the birth." She suggests one to three cups a day after birth to tone and strengthen pelvic tissues.