How did vegeta react when bulma was pregnant?

Answer 1

It was never shown in the anime or manga so it is unkown.

well in episode what like 106-107?... (it may not be the exact episode but around there) when trunks appears and goku is just getting back from his battle on namek with frieza trunks tells goku who he is and that hes the son of vegeta and bulma but... the anime never shows bulma pregnant so i guess there really is no answer to that... that's my best though x3

This is the infamous question to which there will never be an answer. Knowing Vegeta and his persona at the time, he probably was apathetic and just didn't want the baby interfering with his training. But Bulma probably pushed the baby on him several times, and Vegeta, after awhile, warmed up to the idea that he had a son and eventually, as shown, he and Trunks grew close.