PHOENIX (AP) _ A newly enacted Arizona abortion ban starting at 20 weeks of pregnancy is the subject of a hearing Wednesday in federal court.

Abortion-rights groups sued to try to block implementation of the 20-week ban, which would prohibit abortions except those needed to save the life of the woman.

The ban is now set to take effect Aug. 2.

Arizona has permitted abortions until viability, which is when a fetus can survive outside the womb. That's considered to be at about 23 to 24 weeks into a pregnancy. Full term is about 40 weeks.

Supporters say the ban is intended to protect women's health and prevent fetuses from feeling pain. Opponents say the ban is an unconstitutional infringement of due-process rights and puts women's health at risk.