Here is a comprehensive response describing the Supreme Court's decision in the landmark case Roe v. Wade:
In the 1973 case Roe v. Wade, the Supreme Court ruled 7–2 that unduly restrictive state regulation of abortion is unconstitutional. The Court decided that a set of Texas statutes criminalizing abortion in most instances violated a woman's constitutional right to privacy, which it found to be implicit in the liberty guarantee of the Due Process Clause of the Fourteenth Amendment.
The Court divided pregnancy into three trimesters and established a framework of increasing state interest in protecting prenatal life as pregnancy progresses. During the first trimester, the Court ruled that the decision to terminate a pregnancy must be left to the medical judgment of the pregnant woman's attending physician. From approximately the end of the first trimester until fetal viability (the point at which the fetus can survive outside the uterus), the state may regulate abortion only in ways related to protecting the woman's health. In the third trimester, once fetal viability has been reached, the state may promote its interest in the potentiality of human life by regulating or prohibiting abortions except where necessary to preserve the life or health of the mother.
This landmark ruling established that the constitutional right to privacy encompasses a woman's decision whether to terminate her pregnancy, while also allowing states to restrict abortions after fetal viability so long as exceptions are made to protect a woman's life and health. Roe v. Wade remains the leading Supreme Court case on abortion rights, though its precedent has been modified by later decisions.