Mississippi senators on Tuesday passed the final version of a bill that would ban most abortions once a fetal heartbeat can be detected, about six weeks into pregnancy.

Republican Gov. Phil Bryant promises he will sign the bill , which will give Mississippi one of the nation’s most restrictive abortion laws. The 34-15 Senate vote was largely along party lines, with most Republicans voting yes and most Democrats voting no.

“Thank you to the Mississippi Legislature for protecting the unborn by passing the Heartbeat Bill (SB 2116) and sending it to my desk for signature. I look forward to signing it very soon,” Bryant wrote on Twitter.

FILE - In this Feb. 13, 2019 file photo, images of fetuses scroll across monitors in the Senate chamber, as Sen. (Sarah Warnock/The Clarion-Ledger via AP, File)
FILE – In this Feb. 13, 2019 file photo, images of fetuses scroll across monitors in the Senate chamber, as Sen. (Sarah Warnock/The Clarion-Ledger via AP, File)

Felicia Brown-Williams, Mississippi director for Planned Parenthood Southeast Advocates, said women might not know they are pregnant before six weeks.

“So, in effect, the Mississippi Legislature just outlawed abortion for most Mississippians,” Brown-Williams said in a statement.

Legislators in several states, including Georgia and Tennessee, are considering similar bills to ban abortion once a heartbeat is detected. Kentucky’s Republican-controlled legislature passed the final version of a bill Thursday, Republican Gov. Matt Bevin signed it Friday and the American Civil Liberties Union challenged it that day in federal court in Louisville.

Abortion-rights supporters are expected to sue to try to block such laws in other states, including Mississippi.

Opponents of abortion are emboldened by a conservative majority on the U.S. Supreme Court and are seeking a case that could challenge the high court’s 1973 decision that legalized the procedure nationwide.

Mississippi enacted a law last year to ban abortion after 15 weeks. The only abortion clinic in the state filed a lawsuit and a federal judge declared the law unconstitutional. The state has asked a federal appeals court to overturn the ruling.

The New York-based Center for Reproductive Rights represented the Mississippi clinic in the lawsuit over the 15-week abortion ban. It issued a letter Tuesday saying the new bill is unconstitutional.

“It disregards women’s fundamental right to determine when and whether to have children, poses a serious risk to women’s health and creates harmful liabilities for physicians,” said the letter signed by two attorneys for the center, Shivana Jorawar and Elisabeth Smith.

The bill says a physician who performs an abortion after a fetal heartbeat is detected could face revocation of his or her medical license.

The Mississippi bill also says abortions could be allowed after a fetal heartbeat is found if a pregnancy endangers a woman’s life or one of her major bodily functions. The House and Senate both rejected efforts to allow exceptions for pregnancies caused by rape or incest.