By The Associated Press

Arizona's ban on abortions starting at 20 weeks of pregnancy is poised to take effect this week after a federal judge ruled Monday that the new law is constitutional.

U.S. District Judge James Teilborg says the statute may prompt a few pregnant women who are considering abortion to make the decision earlier. But he says the law is constitutional because it doesn't prohibit any women from making the decision to end their pregnancies.

The ban, set to take effect Thursday, prohibits abortions starting at 20 weeks of pregnancy except in medical emergencies. That's a change from the current ban at viability, which is the ability to survive outside the womb and which is about 24 weeks.

The New York-based Center for Reproductive Rights says it and another group plan to file an emergency appeal with the 9th U.S. Circuit Court of Appeals.

Arizona is one of 10 states to enact types of 20-week bans.