A TRADE ASSOCIATION representing a swath of the state’s commercial health insurers is launching a public awareness campaign to let members, pharmacists, and providers know that a 2017 law permits women fully insured through commercial health plans to fill a 12-month supply of oral contraceptives all at once.

The law has already been in effect for three years but, as a CommonWealth investigation revealed, only about 300 women obtained a 12-month supply of birth control last year through the state’s largest insurers, and none had received it through MassHealth, the state’s Medicaid program, according to a source at MassHealth and advocates.

The Massachusetts Association of Health Plans said it is launching an “aggressive awareness campaign” in the form of notices, emails, newsletters, and web pages, some of which will launch as soon as this week. Harvard Pilgrim, Tufts Health Plan, Fallon Health, Health New England, BMC HealthNet Plan, and AllWays Health Partners have all agreed to add information on the issue to their websites.

The group, which represents 16 health and two behavioral health plans, says that the law will impact 40 percent of its membership, as the rest of the members are part of self-funded insurance plans that require employer approval to take part in the benefit.

CommonWealth reported that many health insurers did little to publicize the law’s benefits and even denied coverage to some who asked for it. Pharmacists similarly claimed ignorance of the law, and told some women it didn’t exist. The health insurers are now having pharmacy benefit managers communicate to pharmacies about the law’s provisions.

Sen. Harriette Chandler of Worcester, the chief sponsor of the law, said she has been in talks with the health insurers and others to come up with ways to educate the hundreds of thousands of women who did not know the so-called ACCESS Law even existed.

Chandler issued a statement saying the CommonWealth story “revealed a system-wide failure” to fully implement the law and provides an opportunity to do a better job now. “Women across the state will be able to seize the benefits they have been entitled to under law without roadblocks or frustration,” she said.

Rebecca Hart Holder, executive director of NARAL Pro-Choice Massachusetts, said having access to a 12-month supply of birth control is more important than ever with COVID. “Bay Staters should not have to risk unnecessary exposure to COVID-19 to remain in control of their bodies and reproductive lives,” she said. “It’s critical that leaders in Massachusetts continue to push for full implementation of the law.”