courtesy of
https://www.mobimotherhood.org/MM/article-herbal2.aspx this seems to be a good guideline.
Red Raspberry Leaf (Rubus idaeus)
The raspberry vine is native to both America and Europe. The roots, leaves, and berries have long been appreciated for their nutritive value. Native Americans gave raspberry leaves to women and animals during birth to strengthen and speed delivery, and we learned this virtue from them. Today, pregnant women take red raspberry leaf to tone the uterus, and to prevent hemorrhaging during birth.
Red raspberry leaf tea provides an excellent source of minerals and vitamins during pregnancy. It is thought it may help build breast tissue during pregnancy as do all highly nutritious lactogenic teas. Humphrey records that it does not appear to contribute to over-supply after birth. Red raspberry leaf is said to bring on the milk and make it richer.
Caution - low milk supply: Raspberry leaf tea is astringent (tightens and constricts bodily tissues) and taken as a "single" can be anti-lactogenic for women who are sensitive to this effect. For these women, it is probably safe to use red raspberry leaf as one ingredient in a lactation tea mixture.
Pregnancy caution: Red raspberry tea may stimulate the uterus. To be on the safe side, build up dosage slowly, beginning with one cup per day for a week, two cups per day next week, and so on up to four cups per day. Consult your doctor before taking raspberry tea if you are at risk for miscarriage.
Sources: Health-food stores; herbal pharmacies; online stores.
Dosage and Preparation:
Mothers take up to a quart of red raspberry leaf tea per day during pregnancy. See above. Red-raspberry tea is said to promote milk production the first week postpartum, though stinging nettle or alfalfa may be the better herb if there is risk of low milk supply-see above .
Medicinal tea: Pour 1 cup of just-boiled water over 2 teaspoons of the dried leaf and steep for 5 minutes. Sweeten with a natural sweetener to taste. Build up slowly to 4 cups a day during pregnancy
Red raspberry leaf as a mild beverage: Steep 1/2 teaspoon of dried leaves in 1 cup of just-boiled water for 1 - 3 minutes. Sweeten with a natural sweetener to taste.
https://www.dailymail.co.uk/health/article-1052898/The-herbal-hazards-threaten-unborn-child.html
"But research shows that raspberry leaf may cause pre-eclampsia, a life-threatening condition for the mother in late pregnancy, and make the baby more likely to need special care after the birth."
https://www.expectancy.co.uk/docs/advicesheet04.pdf
Precautions - do remember that raspberry leaf contains powerful chemicals which act in the
same way as drugs – just because it’s natural doesn’t mean it’s safe for everyone. If you’ve had
a previous Caesarean, avoid raspberry leaf as it may put stress the uterine scar. Similarly if
you’ve had a premature labour or very rapid labour, or any vaginal bleeding, either in this
pregnancy or a previous one, avoid raspberry leaf as it may cause contractions. It should also be
avoided if you are expecting more than one baby, or have any serious pregnancy complications
eg severe high blood pressure, breech baby (bottom first) or you’re due to have a planned
Caesarean for specific medical reasons. If you are anaemic & have been prescribed iron tablets,
you should stop the raspberry leaf as it may reduce the amount of iron (& other minerals such as
calcium & magnesium) that your body absorbs. Also avoid raspberry leaf if you’re taking antidepressants.
she was too cosy in their 
