April 18 (Bloomberg) -- The U.S. Supreme Court upheld a law that makes it a crime to perform ``partial birth'' abortions, allowing the first nationwide ban on a procedure as two justices named by President George W. Bush tipped the balance.

The justices, voting 5-4, said the 2003 Partial Birth Abortion Ban Act is constitutional even though it lacks an exception for cases posing a risk to the mother's health. The court also rejected claims that the law is so vaguely worded it would force doctors to forgo a commonly used, constitutionally protected abortion technique for fear of prosecution.