It's looking very unlikely that The Binding of Isaac: Rebirth's Afterbirth DLC will ever appear on Vita, 3DS or Wii U.
Publisher Nicalis' founder Tyrone Rodriguez offered this bleak outlook on Twitter. "Evaluating Afterbirth for Wii U, new 3DS and PS Vita. Not running at a performance level I'm happy with. Outlook NOT good," he wrote in a message retweeted by The Binding of Isaac developer Edmund McMillan.
"The Wii U is not much more powerful than a PS Vita," Rodriguez added in a follow-up tweet.
At a glance, it may seem odd that a fairly retro-looking 2D game couldn't run on Nintendo's latest hardware, but Rodriguez noted that there's a lot going on under the hood, especially as the game lets players stack all sorts of unique weapon combinations. "Among other things, consider that Afterbirth has over 100 weapon combinations, Rebirth had much less. Those stacks add up," he explained.
Rodriguez didn't say anything about the PS4 version of Afterbirth, so that's still sounding likely. If you're near your PS4 you could always opt for remote play if you're really determined to get your Afterbirth on in bed (which sounds all sorts of wrong).