How do you know they are for "convenience"?  That is a very broad assumption. See the Guttmacher report for why women choose abortion.  It's not a simple black and white issue.  It never has been. 

"The reasons patients gave for having an abortion underscored their understanding of the responsibilities of parenthood and family life. The three most common reasons—each cited by three-fourths of patients—were concern for or responsibility to other individuals; the inability to afford a child; and the belief that having a baby would interfere with work, school or the ability to care for dependents. Half said they did not want to be a single parent or were having problems with their husband or partner."  

https://www.guttmacher.org/fact-sheet/induced-abortion-united-states