I may have been influenced by dinking around using MTool and accidentally slipping into the ending, which showed Erika being preggers, but I didn't feel like using the item over having the cut scene deal with it was THAT big a gotcha. When I lost and it broke, I reloaded. When I was finally successful and it didn't get handed off, I checked my inventory for it and saw it was usable. Also, yeah, the english translation straight up says the guildmaster can't give it to her while she's healing because it'd be too much for her body. Considering current emergency contraceptives in the real world are hormone dumps that can cause a host of issues, that's probably valid.After freeing Erika from the rapists, you use the medicine from your key items bag. The guildmaster doesn't give it to her after the minotaur fight because it's too toxic? or something while she's recovering from injuries. It breaks if you get defeated by any of the bandits in the escape sequence and you haven't given it to her yet.
But yeah, feels like a real 'GOTTEM!'
Certain scenes do feel like if you don't get to them naturally, that they don't take into account Serena's virginity status, like prostitution training events (totally cheated myself some silver to skip the grind), and others might reference it in dialogue but not have extra art for it, like a bathhouse scene.