I told my gp I was taking it, she initially told me I shouldn't and then I asked her to read into it and she told me she can't recommend or prescribe it- but it seems to have no adverse affects so if it gives me race of mind to continue if I choose.
Studies have shown it increases chances of healthy baby's after miscarriage where no issues have yet been identified (ie before you have had three so no one cares) as it very slightly increases the blood flow to reproductive organs and stops very minor clots forming - so if blood flow to uterus or clotting was the issue this should help.
I figured if it's not hurting and it may help, why not.
I read to take it till half way through then reduce it gradually until off it for third trimester to reduce risk of excess bleeding during labour.
I take extra 25ug spray of vit d and 100mg magnesium on top of my pregnancy vitamins for same reason. Studies have shown deficiencies in these are linked to miscarriage- nothing I could find suggested they would hinder in any way.