Mississippi has signed into law the tightest abortion restrictions in the US.
The bill bans most abortions after 15 weeks and does not allow exceptions for rape or incest.
The only exemptions will be in cases where foetuses have health problems making them “incompatible with life”, or the mother’s life is in danger.
Governor Phil Bryant has frequently said he wants Mississippi to be the "safest place in America for an unborn child".
Mississippi previously tied with North Carolina for the nation's strictest abortion limits at 20 weeks.
Katherine Klein, equality advocacy co-ordinator for the American Civil Liberties Union of Mississippi, said: "We certainly think this bill is unconstitutional.
"The 15-week marker has no bearing in science. It's just completely unfounded and a court has never upheld anything under the 20-week viability marker."
Jameson Taylor, acting president of the Mississippi Centre for Public Policy, said: "We're thrilled that Mississippi lawmakers are taking a step to protect the basic right to life, as well as protecting maternal health."
