Jessie L. Bonner, Associated Press
Republican Rep. Carlos Bilbao is shown with his copy of the Affordable Care Act in his office at the Idaho Legislature in Boise, Idaho on Friday, Feb. 17, 2012.

BOISE — A measure to allow Idaho employers to ignore new federal rules requiring them to cover contraception in their insurance plans survived efforts to kill it Monday.

Instead, supportive Republican lawmakers on the House Health and Welfare Committee agreed to let sponsor Rep. Carlos Bilbao, R-Emmett, make changes to allay their fears it could keep patients who use prescription birth control for medical reasons besides contraception from receiving necessary treatment.

"I support the motives of the sponsor, but the potential unintended consequences might be something they want to address," said Rep. Ken Roberts, R-Donnelly.

There's no date set yet for Bilbao's changes to be considered.

Bilbao, a devout Catholic, aims to challenge a recent Obama administration decision seeking to guarantee reproductive health coverage for employees of religion-affiliated institutions. That includes contraception, sterilization and abortion drugs.

The federal rule is part of the 2010 Patient Protection and Affordable Care Act, and Bilbao said his bill is necessary to keep employers from being forced by the federal health care overhaul to provide insurance coverage that violates their consciences.

Idaho isn't alone in considering similar legislation, with Missouri and Arizona also mulling changes.

But Idaho's measure appeared headed for the scrapheap Monday, after Republican Rep. Fred Wood, a doctor, proposed killing it outright, on several grounds.

Wood, R-Burley, argued it imposes the religious beliefs of employers on their workers; would likely result in a costly, losing legal fight against the federal government; and is so broadly written it could be used to erect costly barriers to prevent women from receiving appropriate treatment for debilitating ocular migraines and endometriosis, among other conditions.

Oral birth control pills are "used in the treatment of a lot of disease processes that have absolutely nothing to do with contraception whatsoever," said Wood. "They are expensive. Even at Walmart prices, they probably run about $600 per year."

Erin Capener, a Boise resident, told the committee she takes birth control pills to treat polycystic ovary syndrome, whose symptoms include cysts and fertility problems.

"Birth control gives you the ability to not only counter those side effects, but also ensure your fertility later on," Capener said.

The committee room was packed to overflowing for Monday's hearing, with most people on hand to oppose Bilbao's bill.

However, proponents including the group Right to Life of Idaho, an anti-abortion group, lauded his measure as a way of protecting the rights of employers who object to certain drugs that interrupt the natural process of a fertilized egg.

Those include so-called "morning-after pills" that women can take following intercourse to block a pregnancy, said Jason Herring, Right to Life of Idaho's president. The health care overhaul's rule requiring basic insurance to cover such drugs without a co-pay amounts to a government mandate guaranteeing abortion coverage, he said.