A majority of the American public — 56% — oppose so-called fetal “heartbeat” abortion bans when they learn the bans would outlaw abortion before many women or gender minorities realize they are even pregnant, according to a Kaiser Family Foundation (KFF) poll released Friday.

The poll comes as various states consider laws that ban abortion as soon as a fetal heartbeat can be detected, or as early as six weeks of pregnancy. Three states (Ohio, Kentucky, and Mississippi) have already enacted such bans this year, and Georgia will soon be the fourth once Governor Brian Kemp (R) signs a recently passed bill into law.

The poll also confirms what providers and reproductive rights organizations have been saying: abortion opponents use phrases like “fetal heartbeat” because the public is more likely to be sympathetic. But a “heartbeat” ban is a misnomer. At six weeks, there’s no heart that beats in the way that’s commonly understood, as gynecologist Dr. Jennifer Gunter has explained.

When KFF asked people whether they’d support their own state enacting a law like Ohio’s, the public is pretty divided. A larger share (50%) of the overall public said they supported the ban, whereas 44% said they opposed it. There is a pretty stark difference along party lines: 70% of Republicans support the ban; 27% of Democrats support the ban; and 53% of Independents support the ban. Republican women are more supportive (77%) of the ban than Republican men (64%).

But when people learn that “heartbeat” bans actually amount to outlawing abortion as early as six weeks into pregnancy, before many women and gender minorities know they are pregnant and so add up to a near-total ban, 12% changed their mind and said they opposed the restrictions. The poll did not identify the party affiliation of those who changed their minds.

The Supreme Court, in Roe v. Wade, said states cannot ban abortion before the fetus is determined to be viable, which the medical community has determined to be around 24 weeks of gestation. GOP states have continued to pass laws like the “heartbeat” ban to challenge the 1973 landmark decision; various lawmakers who authored heartbeat bans in their respective state have said as much. Lower courts have so far blocked a lot of these bans.

Overall, two-thirds of the public (65%) do not want to see the highest court overturn Roe, while only about one-third (32%) would like to see the decision overturned, according to the latest KFF poll.

This is the first time KFF has done any kind of polling on “heartbeat” bans. The poll offers helpful insight into abortion restrictions, contrasting most public opinion surveys around this complex issue that usually fail to capture the nuance.