Sure, there are health problems, failed contraception, economic reasons (not having money for a child or risk of being fired for being pregnant, etc) and then people who under no circumstance want children. Point is, they still have a right over their body as long as other people have the same right.

If you want to prioritize "life" over body integrity, then you might want to include blood, marrow and organ donation. But if you prioritize body integrity over life in all those other situations, then changing priorities just for pregnancy is out of place.