It's very important to realize that when it comes to weight, it's always relative to the size of the snake you plan on breeding! For example, I have a female normal who weighs in at about 2200 grams, she's not fat and she not the thin, the weight just looks right for her size. Now if she suddenly lost 400 grams, she'd still be considered breedable on paper yet in reality she'd actually be underweight which might cause some worry and prompt me not to breed her. So, when you are deciding to breed this female, take into account weather or not her weight looks good for her size, I've had snakes not feeding and dropping weight on me in the past simply because they're overweight and if that was the case, it'd probably be okay to breed her (just making sure she had a little bit of food to go off of before you did so would probably be a good idea though!) but if she's been losing tons of weight and looks thin it would be best to work her up to her previous weight first.
If you could post a current picture of her it would probably help people determine if she looks good to go or weather or not you may want to consider checking into a vet's office!