 It also reviewed the developments of medical procedures and technology to perform abortions, which had only become reliably safe in the early 20th century.After its historical survey, the Court introduced the concept of a constitutional "right to privacy" that was intimated in earlier cases involving parental control over childrearing ("Meyer v. Nebraska" and "Pierce v. Society of Sisters") and reproductive autonomy with the use of contraception ("Griswold v. Connecticut").Then, "with virtually no further explanation of the privacy value", the Court ruled that regardless of exactly which of its provisions were involved, the U.S. Constitution's guarantees of liberty covered a right to privacy that generally protected a pregnant woman's decision whether or not to abort a pregnancy.