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Advocates for abortion rights don't often get good news, but Wednesday brought some.

The Food and Drug Administration has made a major change in how it labels medication that induces abortion, robbing anti-abortion lawmakers of a key tool they have had to limit access.

The FDA's new labeling for the drug mifepristone approves use for 21 more days into pregnancy — from 49 days of gestation to 70 — and lowers the overall dosage, making it less expensive and reducing side effects.

"We are delighted," said Vicki Saporta of the National Abortion Federation, the major professional association for abortion providers.

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The new move, she said, "brings the label for mifepristone in-line with scientific research and evidence-based practice."

Related: Shuttered: The end of abortion access in red America

According to the manufacturer, since its approval, more than 2.75 million women in the United States have taken mifepristone to end a pregnancy early in its gestation, choosing it over "surgical" abortion that involves dilation and curettage.

The impact in states like Ohio and Texas may be sweeping. But in at least one state, Arizona, lawmakers already have sent a bill to the governor that seeks to thwart the FDA's impact by explicitly requiring the old label. It could become law as early as this week.

Anti-abortion rights campaigners condemned the expanded access to the drug, which was in response to an application and clinical data submitted by the manufacturer, Danco Laboratories.

"It's expanding the customer base for the abortion industry," Randall O'Bannon, director of education and research for the National Right to Life organization.

Danco spokeswoman Abby Long declined to provide sales data for the pill but said it has been used by more than 2.75 million women in the United States since it was approved in 2000.

During a medication abortion, the drugs first block hormone progesterone and then causes the uterus to contract and empty.