Lawmakers in Veracruz made it Mexico's 17th state to pass legislation declaring life begins at conception, then adopted a proposal that requires Congress to consider amending the constitution to outlaw abortion.
A majority of the country's 32 states have now enacted anti-abortion measures in response to Mexico City's legislature permitting abortions in the first 12 weeks of pregnancy.
Mexican states currently set their own laws on abortion, but the constitutional proposal adopted by the Veracruz lawmakers late Tuesday is likely to make the issue a federal one.
Under the constitution, a single state legislature can propose an amendment that must be considered by Congress, and even pro-choice activists said Wednesday that given the makeup of Congress _ and what they called heavy lobbying by the Roman Catholic Church _ Veracruz's proposal stands a good chance of approval.
"This is outrageous, disappointing and very frustrating," said Maria Luisa Sanchez of the Group for Informed Reproductive Rights. "It is very serious that they have brought it up on the federal level."
If both houses of Congress pass the amendment, it would then go to the state legislatures and be enacted if more than half approved it.
"It is in Congress' hands now, to see whether they submit it for study, discuss it and approve it," said Veracruz legislative spokesman Arturo Rodriguez.
Noemi Ramirez, director of the Mexican Academy of Human Rights, said "it is quite probable" that Congress could pass an abortion ban since the governing National Action Party and the Institutional Revolutionary Party _ which supported the state measures _ have a majority in Congress.
"This type of reform is a giant step backward," she said.
The National Action Party did not immediately respond to requests for comment on whether or when its federal legislators would take action on the Veracruz proposal. Nor did the Catholic Church respond to requests for comment.
In 2008, legislatures around the country began approving laws defining life as beginning at conception _ making abortion in most cases homicide _ after Mexico City's assembly legalized abortion the previous year.
Veracruz lawmakers voted 39-6 to adopt the measure.
"Now more than half the states of Mexico have reformed their legislation to defend the right to life and protect women," the legislature of the southern Gulf state said in a statement.
The comment about protecting women was a reference to a clause in the law that gives women convicted of undergoing abortions alternative sentencing, like obligatory "education programs," rather than jail time.
The Veracruz law also includes exceptions for rape, congenital deformation of a fetus or danger to the mother's life.
Rosalia Cruz Sanchez, a pro-choice activist in the conservative state of Guanajuato, said that under the increasing wave of restrictive state laws, such exceptions are often rendered ineffectual.
Cruz Sanchez said that in states like Guanajuato, which enacted a similar law in May, doctors fearing prosecution require a woman impregnated by rape to produce a letter from prosecutors confirming that. She said authorities often delay until the window for such an abortion _ 12 weeks in most states _ has passed, forcing the woman to bear the child.
Activists said it was not clear how many women have been prosecuted under the new wave of state laws. In many states, abortion was already technically illegal but laws were loosely or unevenly enforced.