Baby Irene? Probably not, though.

Barney might be a stickler about protection but Robin isn't. There was an episode-long Robin pregnancy tease after her reckless, unprotected hookup with Ted after their sad anniversary/breakup dinner. It wasn't mentioned whether she was on the Pill but the hint was that she wasn't.

They aren't "the Eriksens." Lily keeping her own last name has been a minor plot point used in at least a few episodes by now.