Weakness in the reproductive tract can be caused by many things, it's not necessarily the ewe's fault she prolapsed, nor is it necessarily genetic. It's far more likely to be an environmental stress or damage.
If she was mine I'd treat her and monitor her offspring, as well as her diet and the flock's diet, and I think that once you figure out the perfect balance for your soil, your flock, their diet, their genes, and all the other factors that must interact properly for all things to be ideal, it'll be fine.... It won't happen again.
Everyone's situation and flock is unique, no two are identical. Raspberry leaf is an incredible toner for the female reproductive system. I use it religiously with births, and they go smoothly as. I only administer it if the female wants it, I don't force them. It works with every female, human and otherwise. Had one collie bitch who wouldn't have contractions unless she had a few sips of raspberry tea. She would stop between pups, for hours, until she had a sip, then contract and birth in the next ten seconds, regularly as. But she always was a lazy one.