"Pregnancy is not a mere inconvenience. “The physical and functional alterations of pregnancy involve all the body systems,” displacing body parts, depleting the body of its necessary elements and changing its chemical balance. The pregnant woman’s body is in a state of constant service, providing warmth, nutrients, oxygen and waste disposal for the support of the conceptus. These activities are always to the detriment of the woman’s body. They are performed for the benefit of the conceptus alone unless an interest of the pregnant woman is also served thereby, that is, unless the pregnant woman defines the pregnancy as wanted."