I found this at babycentre:
It contains a uterine tonic and, taken daily in the last six to eight weeks of pregnancy, it helps to prepare the uterine muscles for labour and thereby ease the process of childbirth.
In a study carried out in Sydney, Australia, 192 first-time mums were given at random either a 1.2g raspberry leaf tablet or a placebo twice a day from 32 weeks of pregnancy. The herb had no harmful effects on mother or baby, and those women who had taken raspberry leaf tablets were found to have a shorter second stage of labour and a lower rate of forceps delivery (19.3 per cent versus 30.4 per cent). However, far more research is needed to confirm these results.
It is very important not to use raspberry leaves until the last two months of pregnancy because of their stimulating effect on the uterus. Start with one cup of tea a day or one tablet and build up gradually to a maximum of four cups of tea or tablets daily. The tea can be sipped freely during labour, too.
You can buy raspberry leaf tablets from health food stores. However many women prefer to make a tea from the dried herb, which is available from some health shops and from herbal suppliers, such as Neal's Yard Remedies. It can also be obtained from a herbalist. To find a registered herbalist near you, contact the National Institute of Medical Herbalists. The tea, or infusion, can be made as follows: put 25g/1oz of the dried herb in a pot and pour on 600ml/1 pint of boiling water. Cover and infuse for 15 minutes. Alternatively, add 1 teaspoonful of the dried herb to a cup of boiling water.
Another herbal remedy that can be used in conjunction with raspberry leaves is squaw vine. Like raspberry leaves, it has traditionally been considered a useful aid to labour and childbirth. As its name suggests, North American Indian women regularly took it in the weeks leading up to childbirth. Like raspberry leaves, it is a uterine tonic which helps to ease labour and birth. There is no research about the effectiveness of squaw vine.
Squaw vine can be obtained from a herbalist in the form of a tincture. She will advise you of how much to take and how often. It should not be taken until the last few weeks of pregnancy.
