abortifacients / contraceptives?

Abortions happen quite often in nature, it was quite surprising when I found that out for a paper I wrote. Many species will abort for multiple reasons, lack of food, or a new male are some of the reasons. Elephants, primates, mice, dolphins, sharks, the list goes on and on. So yes, I can agree that abortions can happen in this game, it should be a possibility even if its through toxic plants (look at Rosencrantz's dilema/concern with Cupid's litter), or through stress, or sheer carelessness (fighting while pregnant could have a female lose the litter i suppose once its far enough along). 

As for a contraceptive, I don't think it's possible naturally. I know you're suggesting a fictional herb, but contraceptives are complicated since it's hormonal, so in my oppinion a contraceptive is not quite possible.

So all in all, in my oppinion; breeding while in heat should always be at risk of pregnancy, but character deciding to abort the litter should be possible