I have tested it in game for several days with no problems at all.
I used Delphy's CAS Texture Unitool to enable the 'maternity' option on these clothes.
I did these for myself, so I figured I would share them so that you can be lazy and not have to do it yourself.
Since there is no pregnancy morph for men as of yet, the easiest way to avoid floaty head syndrome when your male sims get preggers is to enable maternity on them.