If you define "Morality" in the Christian context as that "That which is displeases god" Abortion is perfectly moral. Not only do the vast majority of pregnancies not result in a healthy birth, the bible clearly endorses abortion and the killing of children [evilbible.com]
I really don't understand Christian can claim to be pro lifers when that position is clearly in contradiction with reality (granted this is often not a factor with the religious) but also their holy book.

As you specified "secular" I really can't come up with "a non religious argument for banning the procedure"

I can however come up with a few reasons NOT to interfere with this procedure as I define "Morality" as that which causes the least amount of harm to a person/society. From abortion being the life saving procedure of a woman with an ectopic pregnancy to the (what I consider the unnecessary emotional, psychological and economic expenditure) banning abortion options would impose on women who were infected with the trauma and dna of a violent rapist who imposed his will over her. While talking about this subject the sister of a friend told me about her friend who was violently raped when she was a teenager. She was impregnated by this attack and because her friend was a Catholic, the young girl gave birth to a child she knew it was (god's gift of life). The infant reminded her of the violent attack and gave her much trauma. As the years went her young boy, like his father, displayed violent at home and in school behaviour imposing physical and other harm to many he cam in contact with. The boy who is now a man, like his father, is currently in jail. The mother is a wreck who does not (can not?) work (psychological/emotional issues).

What about a maul formed fetas that is not and will not develop a brain? (this happens. I know of a case) Do you need to make laws demanding the woman carry that to term and make the mother pay for a funeral/casket? I think not.

I think it's wrong to be deliberately having sex without protection simply on the premise that the fetus can always be aborted. That being said, I am still pro choice. If I was a woman, it wouldn't be my preference (yes I have the audacity to imagine what I might do if I was a woman. Deal with it!). But that's just it. It's just my preference. I'm not going to tell others what to do with their bodies.