Oklahoma Governor Mary Fallin has signed the so-called "Fetal Heartbeat" bill into law.
The legislation requires abortion providers to inform women that they have the right to hear the heartbeat their fetus before having an abortion.
Supporters say the measure gives women additional information before deciding to abort.
Opponents say it duplicates state law that allows women to listen to the fetus' heartbeat as part of informed consent laws on abortion.
Fallin signed the bill Friday. It takes effect Nov. 1.