It's been years since I last played one, so idk what the current market looks like for them. I had a couple that I really liked, I'll try to remember them and get back to you if I can think of what they were.
Tales from the Unending Void is probably the best game with pregnancy. I also enjoy Reunion, My Dorm, WVM, Horton Bay... just for the kink tho, their stories are meh at best.
Serena only exists as a single image in the character list, and maybe a mention in dialogue? You could dig up an old version with her old image to compare to, but there's nothing worth keeping.