(Reuters) - Growing numbers of U.S. states are seeking to ensure that women have continued access to free birth control in case the insurance benefit is dropped as part of President-elect Donald Trump’s vow to repeal and replace the Affordable Care Act. The 2010 law, popularly called Obamacare, requires most health insurance plans to provide coverage for birth control without a patient co-payment, which can be as much as $50 per month for birth control pills or $1,000 for long-acting contraceptives such as intrauterine devices. California, Maryland, Vermont and Illinois since 2014 have enacted statutes codifying the Affordable Care Act’s contraception mandate in state law and expanding on the federal law’s requirements. Democratic lawmakers in New York, Minnesota, Colorado and Massachusetts said they are pursuing similar measures this year, with Obamacare under mortal threat in Washington. New York’s Democratic attorney general, Eric Schneiderman, on Wednesday introduced such a measure in his state’s legislature that would expand on the Obamacare contraception mandate. “Women across New York are very concerned that Republican efforts to repeal the ACA will mean the loss of the contraception on which they rely,” Schneiderman said. “I won’t hesitate to act to protect New Yorkers’ rights - including the right to choose, and the right to birth control - no matter what a Trump administration does,” Schneiderman added, referring to abortion rights. Trump, who succeeds Democratic President Barack Obama on Jan. 20, and his fellow Republicans in Congress have made dismantling Obamacare their “first order of business,” as Vice President-elect Mike Pence put it on Jan. 4. [nL1N1EU0RW] Republicans in Congress have not presented a detailed proposal for repealing and replacing the law but many Republicans and religious conservatives have opposed the Obamacare contraception mandate. [nL1N1EU0RW] Twenty-eight of the 50 states currently have laws requiring private insurers to provide coverage for birth control. But not all the laws affect all insurance plans, and only a few mandate cost-free birth control. OUT-OF-POCKET EXPENSES The Obamacare contraception mandate has applied since 2012 to most new insurance plans including employer-provided coverage. In 2013, for example, the mandate saved U.S. women more than $1.4 billion in out-of-pocket expenses for birth control pills, according to a report by University of Pennsylvania researchers. Almost 6.9 million privately insured U.S. women used the pill that year. The legislative move by some states, most of them Democratic governed, is designed to clear up uncertainty for some of the 55 million women who now have access to free contraceptives and related treatments under the Affordable Care Act. Conservatives also have chipped away at the Obamacare mandate in court. The U.S. Supreme Court ruled in 2014 that forcing family-owned businesses to pay for employee insurance coverage for birth control ran afoul of another federal law safeguarding religious freedom. The Supreme Court last May sent another legal challenge by nonprofit Christian employers back to lower courts to reconsider the matter after tossing out their rulings favoring the Obama administration. [nL2N18D0PL] “I think it is even more important now,” said Colorado state Representative Susan Lontine, who last year co-sponsored a contraception coverage bill in her state’s legislature that did not get passed but she expects to be resurrected in 2017. “We don’t know what will happen on the federal level.” California in 2014 became the first state to pass a contraception mandate that went further than the Obamacare language. Maryland, Vermont and Illinois last year passed laws that also eliminated co-pays for vasectomies and allowed women to fill a birth control prescription for at least six months rather than one to three.  The New York legislation would allow women to fill multiple months of a birth control prescription, prohibit private insurers from “medical management” reviews that could limit or delay contraception coverage, and provide coverage for vasectomies without a co-pay. Within a matter of months, the Trump administration even without congressional action could drop contraception from Obamacare’s list of preventive services that health insurance plans must cover without out-of-pocket costs, said Laurie Sobel, senior policy analyst at the nonprofit Kaiser Family Foundation. If repealed, some employers might choose to maintain the coverage without a co-pay because it is a relatively inexpensive benefit popular with employees. The proportion of privately insured women who paid nothing out of pocket for birth control pills increased from 15 percent in the fall of 2012 to 67 percent in the spring of 2014 during the time when the coverage went into wide effect, according to the Guttmacher Institute research organization. The no-cost contraceptives coverage also spurred women to switch to long-acting methods such as the IUD, which is offered in the United States by Bayer, Teva, Allergan and Medicines360, studies have found. More than 77 percent of women and 64 percent of men support the no-cost contraceptives coverage, according to a 2015 Washington Post/Kaiser Family Foundation survey. 