The 9th U.S. Circuit Court of Appeals ruled Tuesday that the law violates a string of U.S. Supreme Court rulings starting with Roe v. Wade that guarantees a woman's right to an abortion before a fetus is able to survive outside the womb. That's generally considered to be about 24 weeks. Normal pregnancies run about 40 weeks
Several states have enacted similar bans starting at 20 weeks. But the 9th Circuit's ruling is binding only in the nine Western states under the court's jurisdiction. Idaho is the only other Western state covered by the 9th Circuit with a similar ban.

http://accesswdun.com/article/2013/5/261732