I believe abortion is only allowable in cases of a medical emergency for the mother (which is uncommon). 

In case you did not know - The overwhelming majority of all abortions, 93%, are done as a means of birth control. Only 1% are performed because of rape or incest; 3% because of fetal abnormalities; 3% due to the mother's health problems.

Here are my reasons for my view given as a response to common excuses for abortion.

1.  Women should be in control of their own body. 

No - "Do you know that your body is the temple of the Holy Spirit, within you, which you have from God? You are not your own; you were bought with a price, so glorify God in your body." 1 Corinthians 6:19-20

2.  Women should not be forced to give birth.

Abortions due to rape account for around 1% of the total amount.  In 99% of the cases no one is forcing two individuals to have sexual intercourse, it is their decision.  If a woman has an unwanted pregnancy, it started with her conscious decision to engage in the act which can lead to pregnancy.

3.  Bringing an unwanted child into the world is bad.

Yes, having unwanted children is bad for the mother, the child, and society.  However, killing and not giving that person a chance at life is worse.

4.  A mother's mental health is more important than her fetus's survival.

No.  Mental health is not more important than life.

5.  Abortion is only done after potential mothers give it serious thought.

So?!  If I think for a long time and make a plan to kill the guy on the corner, I get the death sentence for premeditated murder.  Giving something a lot of thought does not make it moral.

Campaign to end abortion - 40 Days for Life

Abortion is not allowed in the Bible nor in the Constitution!

Links to other studies/articles about abortion that I find informative and/or intriguing.

Reasons U.S. Women Have Abortions: Quantitative and Qualitative Perspectives

Arguments against Planned Parenthood's reasons for abortion