Mn college students petition for 4th Trimester Abortition

Whether or not it comes to pass, just considering this and the people who are signing the petition .......absurd today, not so crazy tomorrow.
Scary

Is this a joke? How can you have a 4th within a "trimester'? "Tri" means three, was there a misprint or are we being played for "sport"?

http://www.huffingtonpost.com/dr-robert-m-myers/fourth-trimester-abortion_b_3665226.html

Abortion for Abortion's sake is what it is.