Vitex Angus Castus in Pregnancy?

My niece has a slight tendency to the symptoms of PCOS and has been trying to get pregnant for the last year. She started taking Angus Castus (400mg x2 BD)in Dec 06 and is now about 6 weeks pregnant. Now she is not sure if to carry on taking it or to stop – could it help to prevent miscarriage by keeping her hormones balanced or could it harm the developing fetus? Appreciate you cannot advise anyone that any 'potion' is 100% safe in pregancy but do you know of cases where Angus Castus has been used in pregancy and for how long it was taken.

No, I don't know of cases where Vitex agnus-castus (chasteberry) has been taken in pregnancy. Because it is used to normalize hormones to promote pregnancy, it is usually discontinued when pregnancy is achieved, because it is an emmenagogue (promotes menstruation).
Occasionally, vitex is used to prevent miscarriage. Simon Mills and Kerry Bone, in their book "Principles and Practice of Phytotherapy" (Churchill Livingstone publisher) say "Use cautiously in pregnancy and only in the early stages for insufficient corpus luteal function". I suggest that you consult with a herbalist-midwife by contacting your country's natural medicine organizations listed in the item "Finding a Herbalist" on the Q&A section of our website www.richters.com :
richters.com/questions-and-answers/02-19991027-1 .