Arizona is now among 10 states to enact versions of 20-week bans. Others are Alabama, Georgia, Idaho, Indiana, Kansas, Louisiana, Nebraska, North Carolina and Oklahoma. North Carolina's ban has been in effect for decades, while Nebraska was the first of the other states to enact its law, in 2010.
A challenge to Idaho's ban was scuttled early on, so Arizona's ban is the first to be tested in court. Arizona's ban is considered to be the most stringent because the starting point it uses to calculate a fetus's "probable gestational age" is about two weeks earlier than under the others states' versions.
In addition to arguing that abortions after 20 weeks of pregnancy are too risky for the mother, supporters of the law argue that fetuses can feel pain at 20 weeks. Critics dispute both points.
Critics also argue the ban could impose hardships on women with nonemergency health problems and fetal abnormalities that aren't discovered until after the ban takes hold.
Janet Crepps, the lawyer representing the three doctors seeking to invalidate the law, argued Monday that Arizona's ban "directly prohibits abortion prior to viability" and because of that "it cannot be saved."
Crepps said the definition of viability should be left up to doctors and not to a state arbitrarily "setting the line" at 20 weeks.
"The act is an undue burden on women seeking abortions," she said.