"In Roe v. Wade, the Court concluded that the "right of privacy, whether it be founded in the Fourteenth Amendment's concept of personal liberty and restrictions upon state action, as we feel it is, or, as the District Court determined, in the Ninth Amendment's reservation of rights to the people, is broad enough to encompass a woman's decision whether or not to terminate her pregnancy." 410 U.S. at 410 U. S. 153. It emphatically rejected, however, the proffered argument "that the woman's right is absolute, and that she is entitled to terminate her pregnancy at whatever time, in whatever way, and for whatever reason, she alone chooses." Ibid. Instead, this right "must be considered against important state interests in regulation." Id. at 410 U. S. 154. The Court went on to say that the "pregnant woman cannot be isolated in her privacy," for she "carries an embryo and, later, a fetus." Id. at 410 U. S. 159. It was therefore "reasonable and appropriate for a State to decide that, at some point in time, another interest, that of health of the mother or that of potential human life, becomes significantly involved. The woman's privacy is no longer sole, and any right of privacy she possesses must be measured accordingly." Ibid. The Court stressed the measure of the State's interest in "the light of present medical knowledge." Id. at 410 U. S. 163. It concluded that the permissibility of state regulation was to be viewed in three stages: "For the stage prior to approximately the end of the first trimester, the abortion decision and its effectuation must be left to the medical judgment of the pregnant woman's attending physician," without interference from the State. Id. at 410 U. S. 164. The participation by the attending physician in the abortion decision, and his responsibility in that decision, thus, were emphasized. After the first stage, as so described, the State may, if it chooses, reasonably regulate the abortion procedure to preserve and protect maternal health. Ibid. Finally, for the stage subsequent to viability, a point purposefully left flexible for professional determination, and dependent upon developing medical skill and technical ability, [Footnote 1] the State may regulate an abortion to protect the life of the fetus and even may proscribe abortion except where it is necessary, in appropriate medical judgment, for the preservation of the life or health of the mother. Id. at 410 U. S. 163-165."