These are maternity pants.
Note the unsightly bag-like material at the front of the pants (arrow). This convenient pocket is for storing the baby, kind of like a kangaroo pouch.
But what do they look like on, you ask?
Well, Philomena here is going to show you.
Um, Phil? Hold still so the nice people can get a look at you.
As you can see, she loves the roomy fit!