The only pro is that if u r selfish enough to not care about murdering babies, then ur body would not get fat & ugly, but that happens to everyone as we get older anyway, so why go through all of the psychological effects of doing it. The only exception is when the baby is dying anyway & carrying it any further would kill the mother. Remember that killing a baby would still deeply effect the mother, most mothers would rather die then see their baby die.
The cons to having an abortion is that there is an immediate connection between mother & child & the mother will always feel as if she destroyed a part of herself. This can become a terrible burden (guilt leading to depression) for the mother that only gets worse & worse. Another reason is that it is murder, no matter if u believe the baby is actually alive yet, it is a new human life forming & as soon as u stop that new life, it is murder. Murder is never right.
The last thing, is that there r hundreds (possibly thousands, although I do not have the statistics) of couples out there that can not have children who would like to adopt. If u do not want the baby, give it to a mom & dad who will love it & take care of it.