Thanks!
To me, and now I'm going to sound cheesy, when you find the person you want to spend the rest of your life with, you make harsh and weird choices. That's why no one (except for Maddie, for obvious reasons) has no problem getting pregnant.
Take Erika as an example. She always compared her boyfriends with the MC, and they were on the losing side of that comparison. Now he IS her boyfriend. He should mess it up big time for that relationship to break (on Erika's side) and she knows him very well and knows that he won't do it. So, for her, it's just the first week of the rest of her life (I'm in cheesy mode today). If she is sure she will spend the rest of her life with him, having kids early isn't a bad thing (in her point of view) since she will be able to travel with the kid when she finishes her degree and accomplishes her dream of being a travel book writer.
Obviously, her reasoning has a lot of flaws, but she's only a small town 18y.o. girl. It's logical for it to have flaws.
The same (each with her own reasons) can be applied to Emma, Daphne, Scarlett, Simone, Megan, Saira or Eileen, the ones who have known the MC for a long time.
Samantha is not eager, but won't be bothered by a pregnancy. She can be counted in the above group, having known the MC since he was 11. But is in a different situation from the below group.
Norah and Martha are eager because of their age and, seeing you play the unpatched version, because they haven't given birth ever and their window of opportunity is closing.
Alexia, the first girl to "see" the harem at the lake, has her own reasons to be happy about her pregnancy. For her, someone with acceptance problems (as she explained while running in the meadow and with her sentence during the "Amanda belongs to the family" scene) getting pregnant is a way to ensure everyone will accept her. Not the MC, he already accepted her. The rest of the family.
And now that the pregnancies have been revealed, the unpregnant girls will be eager to be impregnated. Competitiveness among women can be fierce, and they are walking an uncharted path, so no one will want to be left out.
Yes, any feedback is welcome!