Dude, why such NEGATIVE assumptions? MOST women KEEP their children and RETURN TO WORK--at jobs which are a lot more time-consuming than porn. Duh. I fail to see any mutual exclusion issue...
It's called "day care", "babysitting", or--what the heck--why not bring the baby TO THE PORN SET!?!? It's not like a 6-month-old baby can tell that Mommy is getting ass-reamed by 4 men she barely knows, right? Sure some of baby's milk might get accidentally squeezed out of Mommy during some vigorous mammary mangling, but there's more where that came from.

Baby won't go hungry. Mommy is building up a college fund for baby... by doing porn. Happens all the time.
Most mothers enjoy a little time away from the crying babies to do "grown up" things... like getting their ass caned and their face covered in semen, for instance.

Lowers Mommy's blood pressure.

Not sure at all why the father's occupation matters? Lots of porn actresses are (*gasp*) MARRIED, but pretend to be single to attract more l/users to their fansites.