From the song by Nick Cave & the Bad Seeds, used to describe the depressed feeling you get about the modern world in general. An abattoir is a slaughterhouse, so the term, in a more in depth way, means you feel the world is lining itself up for slaughter, much like cows do at a slaughterhouse.
Man 1: Hey, are you all right? You've seemed kinda depressed lately.
Man 2: Oh, it's okay, I've just got a case of abattoir blues.
This is the second time this year she has come to the abortoir to have her unborn babyterminated. There are approximately 42 million babies killed at abortoirs worldwide a year.
This is not a word. This is similar to "babby" or "peregenant" insofar as it is referring to an aspect of reproduction and/or women's health issues infused with a healthy dose of "didn't pay attention in grade school."