The Louisiana ban would take effect if Roe v. Wade is overturned. Medicaid, which provides health benefits for the poor and disabled, requires funding for abortions in cases of rape or incest. Louisiana would allow those exceptions so long as it was required for Medicaid funding.
Seven states have such abortion trigger laws, and Louisiana already had a trigger law, although abortion legislation has been blocked by courts. The new law would mean the ban would happen quicker in the case of a new Supreme Court decision.
Blanco cited "overwhelming" support for the bill in the state Legislature.
"The central provision of the bill supports and reflects my personal beliefs," she said in a statement, adding she had hoped for legislation with exceptions for rape and incest.
"It is hard to believe that by passing this ban they are addressing what is most on the minds of most of the citizens of Louisiana," she told Reuters.
Most U.S. states have some limits on abortion linked to gestation of the fetus and often based on viability, essentially the ability to live outside the womb.