Austin, Texas – The Texas legislature voted to pass one of the nation's strictest anti-abortion bills, with the governor's signature expected as early as Friday.

The bill bans abortions as soon as a fetal heartbeat can be detected, which usually occurs around six weeks – before most women even know they are pregnant.

Texas has become the 13th state to pass such a bill.

According to the Houston Chronicle, the Texas bill is unique in that it allows pretty much any private citizen to sue abortion providers. The measure, which leaves lawsuits up to everyday people rather than a government authority, is designed to bypass some of the legal holdups that have stalled other states' anti-abortion bills.

The passage came after an amendment was added preventing rapists from suing their victims, but it is unclear whether they have to be convicted. Most cases of sexual assault go unreported.

"The Texas Heartbeat Act is novel in approach, allowing for citizens to hold abortionists accountable through private lawsuits," a Texas Right to Life senior legislative associate said. She explained that the bill "does not punish women who obtain abortions," only providers and people who "aid or abet" an abortion.

Opponents of the bill say it is designed to overburden abortion providers with costly legal fees, as medical providers don't receive any compensation for legal expenses, even if they win their case.

Pro-choice activists plan to challenge the bill before it is set to take effect in September.