First of all, if you haven't already done so, GET THE CAT SPAYED! THAT
ALONE WILL KEEP HER FROM ROAMING IF YOU insist ON LETTING IT GO
OUTSIDE.
Second, keep the poor thing INDOORS!
I am currently saregiver for a family of (now) feral cats. Once upon a
time the mother cat was a pet, now she on her own, raising a family.
Probably becasue she was let to "do her own thing", ended up pregnant
and they abandoned.
Do the right thing and get your cat fixed and keep her indoors!
Cat lover with ATTITUDE