Fated To Love you, both
korean and
taiwanese versions, that's how the couple gets together. And the whole first part of the drama focuses on her pregnancy.
Other dramas I can think of where the main character gets pregnant at some point, but it's not a central moment (as in the focus is for example put more on the child, or it arrives late in the drama...):
Secret, and
Autumn's Concerto (great child scenes in that one). Ah and I have only seen the
movie adaptation, but it must be the case for
Koizora as well. Hmmm... Oh and also
Que Sera Sera.
Good luck!
