The Republican-controlled Iowa Senate has begun debate on a bill that would ban most abortions in the state after 20 weeks of pregnancy. The chamber launched floor discussion Tuesday night. It’s unclear when lawmakers will vote on the measure, though it’s expected to pass. Iowa law bans abortions at the end of the second trimester of pregnancy, or 27 weeks. The bill would ban most abortions after 20 weeks of pregnancy, based on the disputed premise that a fetus can feel pain at that stage.