If you're talking about periods, then I can't imagine how I've survived any dive where there have been sharks in the vicinity, and while I'm not in the 100s of dives yet, I've had a few dozen with sharks around. Any woman on her period isn't exactly just wearing a pad in the water, it'd be a tampon (not entirely sure how well those work, tbh, someone please correct me and jump in if I'm wrong) or a cup. Both of which stop blood from entering the water and cups I know work pretty well for long and moderately deep dives. If a shark can smell blood before it fully exits the body and enters the water, then shark attacks and fatalities would likely be a lot higher.
I'm not very well-versed in shark senses or feeding behavior in that area, but is it possible if there was other prey in the water (someone mentioned pigs) that after the first shark bit, the others were attracted to the thrashing and the blood?