Apologise I may have misremebered that % lol.
Even though i can vouch completly that Enhanced Fertility is 100% successful on fertile women. I should I know I do massive pregnancy runs around the map usually knocking up like 12 girls in a day (i like to make sure they line up with their births so i know when 1 gives birth the bulk of them will as well. The only ones who break this pattern are pets (7 days), goblins (15 days) & vampires (25 days)).
This is really good to know then.
In all my previous playthroughs, I thought the only purpose of the Enhanced Fertility Potion was to impregnate girls who were using the barrenness potion or who were barren through other means.
This revelation saves me some time and effort as I see no real need to invest time, energy, and resources in making multiple vials of the normal fertility potion if the Enhanced Fertility potion guarantees my desired outcome.
My only complaint is that this information (that the Enhanced Fertility Potion provides 100% impregnation chance) was NOT provided either in the wiki or in the walkthroughs/guides.
And I don't think it was provided/alluded to in that priestess' notes.
Her notes only make it seem as if the Enhanced Fertility Potion overcomes barrenness.
