I am sorry she is aborting... that can be a side affect of the deworming or simply from her getting in such low condition. However, many many toxins also cause abortion. I do not want to alarm you but this ride may not be over... if it was actually toxicity from certain plants, the affected animal can often show signs of improvement after supportive therapy only to suddenly abort & then die. I had this happen several years ago. We had 5 fainter goats who managed to find a hole in our fence from storm limb damage & they went over into the neighbors swampy back property. When I arrived home they showed classic signs of poisioning and I immediantely treated them with activated charcol & supportive therapy & atropine. They all seemed to recover over the next 3 days.... at day 5 after ingesting what I now believe was "fetterbush" 2 of the girls spontaneously aborted and the were dead within 2 hours... the other 2 lived 2 more days before doing the same. Taking samples we learned that it was an alkoloid based poison - probably an evergreen type plant (& I found fetterbush on the neighbor's property). What happens is that the toxin concentrates in the unborn fetus, the liver & kidneys. Although we treated them within 5 hours (the time I was away from home - not actual ingestion time) the toxin had already spread into the liver & kidneys. Although it did not kill them within a few hours, we had kidney & liver failure over the next week. Miscarrage of the fetus was the body's last ditch chance of preserving the life of the mothers. Only one of the 5 survived & although she also aborted & was sickly again after the misscarriage, she did come out of it with no longterm issues.... bloodwork shows her liver & kidney functions within normal ranges a month after exposure.
This was a horrible thing to go through.... I ultimately felt guilty & almost sold out of all of my animals. But things happen.... my fences are good - just had storm limb damage I hadn't found on the 24 acres. I keep my pastures mowed, walk them often & am familiar with the common flora here. Needless to say, there are actually 2 perimeter fences now.... the inner fence is the limit that the goats & sheep can go in, the outer limit holds the donkeys & cows.
Normally, my goats would have not ate this plant.... but it was about this time of year, little greenery in the pasture & cold & icy. They were tired of hay & found something "green" on the neighbor's land. So I learned a heartbreaking but valuable lesson. Now the sheep & goats are pastured on the front of my property in the winter - easier to see them constantly, more predator proof and less "weeds" on this 4 acre pasture - rotate them from the 4 acre to a 2 acre every 4 to 6 weeks to help with parasite control. In spring after the lambs & kids are about 4 weeks old, I turn them into the main big pastures & rotate them following the horses from the 5 acre pastures in a large circular movement until we are back at the front pastures.
Again, I hope your issue was just parasites.... but please keep an eye on your girl as this may not be over. Best of luck...