I have seen and reviewed pregnant providers. Liked them a lot. Early in my hobbying career, my ATF was popping out a kid every 11 to 13 months, had two while I knew her. Her nipples were huge and I always enjoyed a drink of her sweet milk.
"Tell your baby I'm sorry I stole her lunch."
Saw another one recently, twice, just before she popped. Pregnant girls are probably the only young (20's) providers I see, all the rest are over 40 with grown kids.