Massachusetts Attorney General Martha Coakley has added charges to a complaint it filed in Suffolk Superior Court against a health insurer and 2 affiliates.

The amended suit against MEGA Life and Health Insurance Company, Mid-West National Life Insurance; and their parent company, HealthMarkets Inc., North Richland Hills, Texas, raises new allegations of unfair and deceptive trade practices.

Coakley’s complaint charges the insurance companies misrepresented the terms of their policies and failed to cover health benefits and services required by Massachusetts law.

The original complaint, filed October 2006, charged that MEGA failed to cover outpatient contraceptive services mandated by Massachusetts law and illegally excluded benefits for some patients with pre-existing conditions.

The new complaint claims that MEGA and Mid-West failed to abide by state law by denying claims for benefits, such as maternity health care, pap tests, contraceptive services, infertility treatment, mammography and preventive care for children up to age 6.

The Attorney General’s action seeks to stop the alleged violations, require the companies to pay refunds and restitution to affected residents and order them to pay civil penalties and costs to the state.

The new complaint also alleges that MEGA unlawfully required membership in a third-party association as an unlawful condition for self-employed individuals and small businesses to obtain insurance.