By BOB LEWIS AND LARRY O'DELL

Associated Press

RICHMOND

--Virginia Health Commissioner Karen Remley resigned Thursday over new GOP-backed regulations that could shutter most Virginia abortion providers as reproductive rights take center stage in pivotal Senate and presidential races.

Her resignation comes a little more than a month after the state Board of Health, coerced by Virginia's Republican attorney general, adopted new requirements that abortion clinics meet the same strict building standards as new hospitals. Abortion-rights advocates argued the strict standards could force most of the state's 20 clinics out of business.

"Unfortunately, how specific sections of the Virginia Code pertaining to the development and enforcement of these regulations have been and continue to be interpreted has created an environment in which my ability to fulfill my duties is compromised and in good faith I can no longer serve in my role," Remley, a career health professional, wrote in her resignation letter to Republican Gov. Bob McDonnell. Her resignation is effective immediately.

The board initially exempted existing clinics from the tough construction standards, but Attorney General Ken Cuccinelli refused to certify those standards. The confrontational conservative, who's running for governor next year, contended that the board exceeded its authority and suggested that he might refuse to represent any member sued over the issue.

Abortion rights has been a key issue this election season in the swing state that could determine whether the Democrats retain their narrow U.S. Senate majority and whether President Barack Obama is re-elected.

Former Gov. Tim Kaine, a Democrat who appointed Remley before McDonnell reappointed her, seized on the issue hours before his fourth and final debate with Republican George Allen in their close Senate race.

"It's unfortunate that a political focus on limiting women's access to health care has prompted her resignation after many years of diligent and faithful service to the Commonwealth, but I know Karen has many years of service still ahead of her," Kaine said in a statement.

Kaine has pressed the abortion issue hard in an effort to keep a lead among women voters. He has noted that Allen has supported "personhood" legislation that could effectively ban all abortions and some forms of contraception by conferring full legal rights on embryos from the instant of conception.

In her letter to McDonnell, Remley said she had honored her commitment to lower abortion rates.