After Roe v. Wade, the polarization of supporters and detractors of the right to abortion resulted in both legislative restrictions on abortion and legal battles to protect Roe. The U.S. Supreme Court had several opportunities to revisit Roe, and each time the Court upheld it, albeit weakening its foundations. Between 1988 and 1989 Pennsylvania's legislature passed five amendments to the Pennsylvania Abortion Control Act of 1982. The provisions required that women must give express consent and receive specific information at least 24 hours prior to the procedure; underage girls must obtain parental consent or judicial authorization; married women must sign a statement indicating that they had notified their husbands; and abortion clinics must comply with a series of reporting requirements. In Planned Parenthood of Southeastern Pennsylvania v. Casey, the U.S. Supreme Court upheld all but the spousal notification requirement. It even reversed sections of prior decisions to uphold the information and waiting-period requirements.

Casey came as a surprise to conservatives and liberals. It reaffirmed Roe, clarifying what the majority viewed as its “essential holding”: (1) recognition of the right to choose an abortion before viability without undue interference from the State; (2) “confirmation of the State's power to restrict abortions after fetal viability,” with limited exceptions; and (3) recognition of a state interest from the outset of the pregnancy in “protecting the health of the woman and the life of the fetus that may become a child.” Casey relaxed Roe's standard of review by moving from strict scrutiny to “undue burden.” Under the new standard, the means chosen by states to further their interest in potential life pre-viability “must be calculated to inform the woman's free choice, not hinder it.” Given that Casey upheld all but the spousal notification, the bar for what constitutes a “substantial obstacle” was left very high. Casey also ended the trimester system, and viability became the dividing line between women's liberty to choose and the right of a state to ban abortions. As a result, the timeframe during which women have access to abortion is more uncertain than Roe envisioned.

Although in practice Casey reduced women's opportunities to access safe abortions by giving more deference to states’ interest in potential life, parts of its reasoning supported women's citizenship and equality, something Roe did not do.