Isn’t pregnancy supposed to tire a person out? Not in the case of Kansas City Chiefs quarterback Patrick Mahomes‘ fiancée, Brittany Matthews. The first time mother to be just powering right through her rigorous workout routines despite her growing baby bump. The 25-year-old certified personal trainer showed off a series of glute and hamstring workouts in a Nov. 25 Instagram video that looked challenging for any normal person, let alone an expectant mom with a prominent baby belly.