They already have a minor side effect, the pregnant's woman hair grows quickly and extremely long throughout the pregnancy. Gloriana had to experiment as it is part of the invention process for the Case, and everything else she created in Winter 1121 (including Potions of Creation, from her Lab Texts) suffered the new Experimentation rolls.
That...is pretty major. 
Fertility Magic already showing much promise!
Oooh, I like it!