I heard this argument once. "When man agrees to live in society, he agrees to compromise on his individual liberties." The assumption there is that these liberties, if unchecked, cause conflict and threatens the peace of society. My inference is that the exercise of one's personal freedom becomes problematic only when it encroaches on the liberty of others.
Liberty of one's own life is fairly easy to understand. One should not deprive the life of another. The issue becomes complicated in the case of abortion. The subtleties of the argument rests on the definition of what is considered life? But essentially the pro-life argument holds life sacrosanct over and above the humiliation/ discomfort/ financial difficulty imposed by carrying the child to term. This pro-life argument feels fine to me. However, it is somewhat weakened by the "sentient being" argument. ie. we hold the rights of sentient entities at a higher pedestal than beings that are not yet sentient. Since a child has not fully developed his faculties, it may be somewhat permissible to deprive it of its life. But this line of reasoning is fraught with danger.... as there are lots of other individuals who may not be considered sentient in the perfect sense.
Then we consider the immense social trauma associated with unwanted pregnancies. It is deeply personal trauma and the burden of raising the child rests on the mother. This burden essentially deprives the mother of her enjoyment of her other liberties like the pursuit of happiness. However, we think of liberties to have certain order of precedence over one another, and its difficult to think of a right to a specific liberty which should outrank the liberty to life.
I have for the most part of my life, been naturally pro-choice. This was perhaps attributable to the fact that pro-life is often touted by religious groups, whose opinions on liberty I hold at very low esteem. But it seems that I cannot find myself a rationale strong enough to embrace pro-choice emphatically.