A Texas law banning abortions as early as six weeks into the pregnancy took effect at midnight Tuesday, becoming the most restrictive anti-abortion law in the US.

Senate Bill 8 (SB 8), signed by Governor Greg Abbott in May, will allow any private citizen to sue abortion providers for up to $10,000 per person involved. The new bill has banned abortion when an ultrasound can detect a “heartbeat,” often before the woman knows she is pregnant. This measure is different from other abortion preventative laws of its kind, as it cannot be enforced by the date, but the plaintiffs may be entitled to significant financial damage instead.

Women and abortion rights activist groups filed an emergency motion Friday to block the law from coming into effect, butthe request was denied by the US Court of Appeals for the Fifth Circuit. The Supreme Court declined to block the bill from taking effect following the request for emergency relief filed on Sunday. The motion stipulated that these restrictions would undermine the landmark Roe v. Wade decision in 1973 where abortion was legalized under certain circumstances.

Previous attempts to restrict abortion in Texas include House Bill 2 in 2013, which required abortion clinics to meet strict standards, essentially making it more difficult for abortion clinics to remain open. The measures from the bill were struck down by the Supreme Court, upholding Roe. However, further abortion bills remain in consideration, such as Senate Bill 4, which will prevent providers and physicians from giving patients an abortion-inducing medicine if they are beyond seven weeks along.