I don't recall anyone making the statement on this forum (or in practice) without explaining why it came as a shock. The way it came across on the video was odd because of that.
This one:
https://www.jehovahs-witness.com/topic/205990/im-pregnant
No explanation. Not that she owes one. But everyone congratulated and wished her. No one mentioned that it was odd or asked for an explanation.
My point was that a couple can get surprised by pregnancy and this couple in the video is no different.