WASHINGTON, DC - MARCH 27: (L-R) Kevin Farrelly, Lisa Dowling, and Rachel Wolf, who are for the healthcare bill and celebrating it, protest in front of the Supreme Court, on the second day of a three day process of hearing arguments concerning the legality of the Health Care Bill, activists gather and protester, on Capitol Hill Tuesday, March 27, 2012. (Melina Mara/THE WASHINGTON POST)

The nation’s largest health insurer will keep in place several key consumer provisions mandated by the 2010 health-care law regardless of whether the statute survives Supreme Court review.

Officials at UnitedHealthcare will announce Monday that whatever the outcome of the court decision — expected this month — the company will continue to provide customers preventive health-care services without co-payments or other out-of-pocket charges, allow parents to keep adult children up to age 26 on their plans, and maintain the more streamlined appeals process required by the law.

UnitedHealthcare would also continue to observe the law’s prohibitions on putting lifetime limits on insurance payouts and rescinding coverage after a member becomes ill, except in cases where a member intentionally lied on an insurance application.

The provisions are part of a larger package in the law often referred to by supporters as “the Patients Bill of Rights” that took effect as plans renewed after Sept. 23, 2010. They are popular with consumers and relatively uncontroversial among insurers. And there had already been signals from industry insiders that some insurers were likely to leave them in place. UnitedHealthcare, a UnitedHealth Group company, is the first to publicly commit to the idea.

“The protections we are voluntarily extending are good for people’s health, promote broader access to quality care and contribute to helping control rising health care costs,” Stephen J. Hemsley, president and chief executive of UnitedHealth Group, said in a statement. “These provisions are compatible with our mission and continue our operating practices.”

The court’s options include upholding the law, overturning part or all of it, and delaying action until after the law takes full effect.

A spokesman at UnitedHealthcare said officials chose to announce their intentions now because “people in this uncertain time are worried about what might happen to their coverage and we think the time is right to let people know that these provisions will continue and they can count on us.”

The announcement applies to the roughly 9 million consumers in plans that they or their employer have purchased from UnitedHealthcare. An additional 27 million people are covered by plans that are administered by UnitedHealthcare but for which their employer has assumed the financial risk, meaning that in effect their employer is their insurer. In these cases it would be up to the employer to decide which provisions to continue offering voluntarily.

While UnitedHealthcare would include birth control and sterilization among the preventive services it would continue to offer without co-payments, officials said they would honor requests from employers or individual customers wishing to remove such services from the list because of religious or other objections. By contrast, in implementing the health-care law’s preventive-services requirements, the Obama administration has issued controversial restrictions on the types of employers that can refuse to offer birth control coverage on conscience grounds.

Officials at UnitedHealthcare said they did not have statistics on what, if any, impact the decision could have on premiums.

The Obama administration has estimated that on average the law’s early consumer mandates would increase premiums by less than 2 percent. However, that figure has probably varied depending on whether a particular plan already included the new requirements — often the case with plans bought by large employers — or whether insurers had to incorporate the new rules — often the case with plans sold to individuals and small businesses.

Further complicating the picture, other forces, such as a drop in use of health care, have exerted a countervailing downward pressure on premiums in recent years.

The “Patients Bill of Rights” also includes several mandates that UnitedHealthcare did not pledge to continue complying with in the event the Supreme Court invalidates the law. These include the elimination of annual limits on insurance payouts, which are being phased out under the law, and that statute’s ban on denying coverage to children with preexisting conditions.

The latter would be impossible to do unilaterally, said UnitedHealthcare officials, because the company’s risk pool could be quickly skewed toward sick children. But in a statement they said the company is “committed to working with all other participants in the health care system to sustain that coverage.”

Ronald Pollack, executive director of the consumer advocacy group Families USA and a supporter of the law, welcomed UnitedHealthcare’s announcement.

“It would make a huge difference for a great number of people who would otherwise be left out in the cold in terms of getting coverage,” he said. “And hopefully, given UnitedHealthcare’s market share, this would have tremendous influence on other companies.”

But even if the entire insurance industry followed suit, Pollack said, it would hardly make up for the loss of other provisions in the law that are set to take effect in 2014 — including the extension of Medicaid to cover a larger share of the poor, subsidies to help low-income Americans buy insurance and bans against insurers discriminating against adults with preexisting conditions.

This would be a “one-third of a loaf” substitute, Pollack said. “A very good step, but in no way altering the necessity of implementing the much larger protections included in the new law.”