For people new to this game, asking about preg and birth: you need an apple, a rare thing (DO NOT EAT IT!), sometimes you get it from giving water to the hidden, dry plant. Sometimes you get an apple as a "thank you", other times the scumbag just attacks you. The last big boss, her lunatic brother, also gives an apple when defeated (and that's harder than hell).
And to make the potion, you must also buy the skill (recipe) for, like, 10k. And then the "birthing scene" itself ain't much to dance a happy jig about.