Former US President Barack Obama and House Speaker Paul Ryan, the Wisconsin Republican. Getty Images/Pool

Last-minute changes to the proposed Republican overhaul of the US healthcare system may not be limited to the individual insurance market, according to a new report.

An analysis from The Wall Street Journal's Stephanie Armour and Michelle Hackman found that a provision in a recent amendment of the American Health Care Act could allow employers to gut some of Obamacare's biggest health-insurance protections for their employees.

The amendment would allow states to apply for waivers to rescind two major regulations of Obamacare, if the state can prove that healthcare costs would decrease as a result. That has led to concerns about its potential effects on the individual insurance market, but it could also change insurance for people that get coverage through their employers.

One of those Affordable Care Act-implemented protections — called essential health benefits (EHB) — requires insurers to cover a baseline of 10 health procedures and items including emergency-room visits, prenatal care, mental-health care, and some prescriptions.

Under Obamacare, employer plans could not place a lifetime limit on the amount that the plans pay out on EHBs, and required plans to limit the amount of out-of-pocket costs an employee had to pay annually, according to The Journal. That made plans more costly for employers but also provided better coverage for employees.

In 2011, The Journal says, the Obama administration said that companies could select whichever state's regulations they wanted for their insurance plans. But that had little practical effect because EHBs were mandated nationwide.

Yet the AHCA could allow a firm to drop these protections for employees by choosing regulations from a state-granted waiver.

Here's an example:

A company could have operations in South Carolina and Vermont. If South Carolina is granted a waiver and drops the lifetime limit on maternity care for insurance plans, the company could use that baseline to put a lifetime cap on maternity care for employees in Vermont as well.

Roughly half of all Americans get their insurance through their workplace, so any weakening of those protections could be wide ranging.

It remains to be seen if employers would be willing to drop the protections. Larry Levitt, a senior vice president at the Kaiser Family Foundation, a nonpartisan health-policy think tank, told The Journal that many employers might continue to provide these protections to be competitive in attracting talent.