pregnant pause
A long pause in speech that indicates a lot of meaning or significance. There was a pregnant pause when the topic changed to Grandpa's will, and everyone could tell that something shocking was about to be revealed. The most telling part of his speech was the pregnant pause before he denied any wrongdoing.
a pregnant pause (or silence)
a pause or silence that is laden with meaning or significance.a pregnant ˈpause/ˈsilence
a pause/silence in which everyone is waiting or listening for something, or a moment of silence which is full of meaning: There was a pregnant pause while everyone waited to hear what she had to say.