4yo regressing before baby?

My son is 4. Will be 5 next month. I am 39 weeks pregnant. Lately he has been regressing in terms of testing limits and rules which I expected.

What I didn’t expect is the potty training regression! He had started wetting the bed (he used to occasionally but now it’s several times a week) on 2 or 3 occasions he has wet his pants during the day and today he pooped in his pants!

He has been potty trained since 2 and has had the occasional accident but nothing this regular.

Is this because of the baby’s impending arrival? Tbh I’m worried what it’s going to be like after baby if we are having these problems already.