The House is scheduled to vote on a bill that would ban abortions in the District of Columbia after 20 weeks of pregnancy.
The bill is based on the disputed claim that fetuses can feel pain at a gestational age of 20 weeks or older. The National Right to Life Committee, an anti-abortion group, has made the bill its top priority on Capitol Hill this year. Nine states have passed similar legislation.
The bill is being considered Tuesday under a suspension of House rules, which means it will require a two-thirds majority to pass. It has 223 co-sponsors, a slight majority, but is not expected to garner a supermajority.
Abortion-rights advocates say the bill is an attempt to roll back a woman's constitutional right to an abortion.