Can Wormer make a mare miscarry?

Question
I recently bought a Quarter Horse mare that had a yearling and was bred back. The mare is roughly 10-12yrs old. Once I got her to my house I rode her a few seconds and also rode her the next day before we turned her into the field where she would be staying. Before I turned her loose I wormed her. I'm pretty sure the box didn't say any thing about "safe for pregnant mares". When a horse I owned 2yrs ago was pregnant I was very careful about what I gave her and made sure any thing I gave her said "Safe for mares in foal"...And her baby turned out fine....I guess my question is...Can wormer cause a mare to miscarry? Or do you think she could have lost the baby cause of the stress of moving from her home to a new place, and then being ridden?

Answer
I moved a pregnant mare to my house and she was just fine so that should be ok....as for the worming....I am not 100% postive but I dont think it will harm your mare....but just to be on the safe side I would get professional help from a trainer or a vet. I know this has nothing to do with your question but Please make sure your field does not have any phescue (spelling may be wrong) grass in it. My mare lost her foal because we turned her out everyday in the pasture and there was phescue in it and we didnt know about it and her baby was born 3 months early and she had no milk or anything and the baby was sick and it died that day. So you also may want to check to see whats in your field. I hope this helps and good luck