I'm surprised with the existence of something like .50 GI we don't see more "wise guys" recommending that over .45, I mean, it's bigger! I guess because Walmart doesn't sell the ammo is why.
Anyway, priority is and has always been the gun you shoot best with in the largest caliber that you are comfortable carrying. For most women, they're not going to want to shoot anything bigger than .22, but that's really an option for last resort. The .380 in an LCP makes my hand shake after a few mags, so for a woman I can imagine it will take less than 10 rds to get the shakes.
.32 ACP, a .32 revolver, or a .38 Special with a light load are better than a .45 for a woman. Heck, a Glock 43 wouldn't be a bad choice either.