Ban beginning at six weeks, which is before most women know they are pregnant, is blatantly unconstitutional

The state capitol in Nashville. Photograph: Mark Humphrey/AP

Republicans in Tennessee have voted to ban abortion as early as six weeks after conception, in a surprise midnight vote held in the middle of a pandemic, without members of the public present.

The ban beginning at six weeks, which is before most women know they are pregnant, is blatantly unconstitutional and will almost certainly be blocked in the courts before it goes into force. Reproductive rights advocates were swift to promise a challenge.

The bill was not listed on the state legislature’s calendar and the vote took place in Nashville in a state capitol closed to the public because of the coronavirus pandemic.

The rate of new coronavirus cases in some Tennessee counties has risen, although the state’s weekly trend has plateaued.

Alexis McGill Johnson, acting president and chief executive of the Planned Parenthood Federation of America, said: “It is a disgrace that in the face of a true public health crisis, Tennessee politicians wasted their time with this last-minute move to attack abortion access before closing up shop this session.”

According to a local reporter, the only protesters present during debate were three women in masks who “snuck” into the public gallery. Placed in handcuffs by all-male capitol police, they yelled “Banning abortion in Tennessee does not save lives!” and “Pro-life is a lie, we don’t care if women die!”

The bill is almost certain to pass into law, as it was proposed by the state’s governor. It comes just days before the US supreme court is expected to issue an opinion in the most highly anticipated abortion rights case in decades.

Abortion is legal in all 50 US states, despite a recent spate of bans. The procedure was legalized to the point a fetus can survive outside the womb by the US supreme court in 1973, in the landmark case Roe v Wade.

The upcoming ruling is expected to indicate the nine-member court’s appetite for restricting abortion. The panel has a 5-4 conservative majority, thanks to the confirmation of two justices nominated by Donald Trump. Notably, all the conservatives are men.

During debate in Tennessee, Gloria Johnson, a Democrat from Knoxville, said: “I feel like there was a bargain made on my reproductive health rights in order to get the budget passed.”

The headline restriction of the new bill is a “heartbeat” provision, which bans abortion after fetal cardiac activity can be detected, which is typically between six and eight weeks after conception. At that stage, a pregnancy is still classed as an embryo. The chambers of the heart and the circulatory system are not yet formed.

The bill also requires abortion clinics to post a sign and provide information telling patients medication abortions may be reversible – although there is no medical evidence to support the claim – under penalty of a $10,000 fine.

It bans abortion outright for juvenile women in state foster care and bans abortion if sought because of a Down’s syndrome diagnosis, or because of gender or race. There are no exceptions for cases of rape or incest.

The bill also requires doctors to perform an ultrasound and forces women to view images of the fetus and to listen to cardiac activity and a description of its limbs and organs. Those requirements are likely to drive up the cost of abortions, which are primarily obtained by young and poor women.

The ban is also sequential, according to the Tennessean. If a court strikes down a provision banning abortion at six weeks, a ban will automatically be instituted at 10 weeks, then 12, 15, 18, 20, 21, 22, 23 and 24 weeks. A full-term pregnancy is 39 weeks after a woman’s last period. A fetus can live outside the woman at 24 weeks, although it is more likely to suffer severe disabilities. Abortions late in pregnancy are extremely rare.

“Hopefully we can protect more lives, we can save more babies,” said the Republican state representative Susan Lynn, according to local news station WJHL.

Despite the pandemic, Tennessee Republicans have refused to pass a bill to expand health insurance to 280,000 low-income residents who have no access to the healthcare system. According to the Kaiser Family Foundation, more than 666,000 Tennesseans lack insurance, including more than 77,000 children.