It's not a Constitutional Amendment, and it's not waiting for another opening on the Supreme Court so that a strict-constructionist can get appointed to overturn Roe vs. Wade. Phyllis Schlafly wrote about it in her book "The Supremacists" and there is actually a bill in Congress that was introduced that utilizes her strategy.
What is it? Have Congress pass a law that takes away the ability of the federal courts to rule on state laws that protect life. HR300 is also called the "We the People Act":
We the People Act - Prohibits the Supreme Court and each federal court from adjudicating any claim or relying on judicial decisions involving: (1) state or local laws, regulations, or policies concerning the free exercise or establishment of religion; (2) the right of privacy, including issues of sexual practices, orientation, or reproduction; or (3) the right to marry without regard to sex or sexual orientation where based upon equal protection of the laws.Allows the Supreme Court and the federal courts to determine the constitutionality of federal statutes, administrative rules, or procedures in considering cases arising under the Constitution. Prohibits the Supreme Court and the federal courts from issuing any ruling that appropriates or expends money, imposes taxes, or otherwise interferes with the legislative functions or administrative discretion of the states.