The United States Supreme Court has held that statutory provisions requiring a physician to exercise a high degree of care to preserve the life of a fetus which "may be viable" are unconstitutionally vague.
Colautti v. Franklin, 439 U.S. 379 (1979).
Constitutional Law - Abortion - Statutory Interpretation - Void for Vagueness,
Duq. L. Rev.
Available at: https://dsc.duq.edu/dlr/vol18/iss1/14