The Mississippi state Senate has passed a bill that would ban abortions after 15 weeks – a move that would give it the strictest limits in the US.
The Gestational Age Act still has to go back to the House for second approval.
If it passes, Governor Phil Bryant has said he will sign the measure into law, adding that he wants Mississippi to be “the safest place in America for an unborn child.”
Similar moves in other states have been blocked by legal challenges.
Currently, Mississippi prohibits abortions from 20 weeks, unless her life is in danger or in cases of fatal foetal abnormality.
The new proposal would move that forward five weeks, and makes no allowances for rape or incest for later terminations.
It has already passed in the state House of Representatives, but has to return for secondary approval before being approved by Governor Bryant.
Diane Derzis, who runs the only abortion clinic in the state, has said that she believes the bill is unconstitutional.
She has said the clinic would consider a legal challenge if the bill is signed into law.
In 2014 federal judges ruled that attempts for six- and 12-week bans in North Dakota and Arkansas were unconstitutional, and struck them down.
“These groups are tossing anything and everything out there, anything that could start winding its way through the legal system because we’re in a very fragile place right now,” Ms Derzis told local newspaper the Clarion Ledger.
“Roe is clearly in danger and that’s what they’re preparing for,” she said, referring to the landmark 1973 Supreme Court case, in which judges decided women had the right to abortions.
“They hope by the time they get to the Supreme Court they will have changed the Supreme Court.”
President Trump has supported a proposed federal ban on abortions after 20 weeks after fertilisation, but the bill was blocked in the Senate in January.