Conservatives tend to believe that pregnancies are generally the result of consensual, unprotected sex between adults.
They tend to believe that the onus is on the woman not to become pregnant and that regardless of her wishes, the stage of pregnancy, her health, the health of the foetus, her circumstances or any number of other factors, she does not have the right to control a process happening inside her own body.
Conservatives also tend to believe that people have 'souls', that these magically appear after conception and that their continued existence takes precedence over the woman's bodily autonomy.
Liberals tend to be aware that someone becoming pregnant isn't necessarily as straightforward as consensual, unprotected sex.
Liberals tend to be aware that pregnancy can result from protected sex because it isn't 100% reliable, pregnancy can be a result of rape, pregnancy can be dangerous to the fetus of a woman with certain autoimmune disorders, pregnancy can be dangerous for women with certain health conditions.
Liberals tend to believe that ultimately, pregnancy is a huge endeavour, it takes a massive toll on the body both physically and psychologically, it can can cause both physical and mental health problems, some of which are dangerous.
There are countless potential complications, some of which can be caused by being in a medical environment, rather than prevented (look up epidural complications) and that to force anyone to unnecessarily experience this horrendous toll on the body and mind is nothing short of barbaric.