The "heartbeat" bill, as it has come to be known, requires women to have an ultrasound to screen for a foetal heartbeat before they can receive an abortion. Critics have argued it will make having an abortion illegal before most women even realise they are pregnant.
The bill exempts women seeking abortions in cases of rape or incest, or if the pregnancy threatens the woman's life. The bill follows an increasing move towards restricting abortions across the US ahead of the November midterm elections.