Since the passage of the Affordable Care Act (ACA) in 2010, officials across all levels of government have been preparing for the law's sweeping changes to the health care system. For many state legislators, those preparations have included enacting new restrictions on the availability of insurance coverage for legal abortions.

When the online insurance marketplaces erected under the ACA become operational, shoppers in only about half of U.S. states will have access to health plans that cover abortions. The federal law permits states to decide whether or not plans offered through the online exchanges can fund those procedures. According to data compiled by the Guttmacher Institute, a research organization focused on sexual and reproductive health and rights, 23 states have banned abortion coverage from insurance plans sold via the health care exchanges—usually making exemptions only in cases of rape or incest or when the woman's life is at risk.

Under previous laws, only eight states explicitly prevented private health insurance plans from covering abortions. The shift, says Elizabeth Nash, state issues manager at the Guttmacher Institute, “means that more women will be paying out of pocket for abortion care.” In the long run, Nash says, the new restrictions may have ripple effects, potentially affecting those who do not purchase an online plan, such as women who receive health insurance through their employers. “The concern is that with so many states limiting abortion coverage, insurance plans will simply stop offering abortion coverage,” she says. The National Association of Insurance Commissioners and trade group America's Health Insurance Plans both declined to comment on the possibility.

In several states, such as Arizona, North Carolina, Ohio, Oklahoma and Wisconsin, the new restrictions follow recent squeezes to family-planning funds that could help fuel clinic closures. A handful of the 23 states are expected to offer separate insurance riders that would allow women to shell out extra money for abortion coverage, but it remains to be seen how many buyers will invest in that option or even how they would find out about it.

The average cost of a first-trimester abortion is just under $500. Without insurance coverage, more women could find themselves weighing difficult financial trade-offs or seeking help from nonprofits to foot the bill.