Some of the nation’s biggest health insurers will keep some popular parts of President Barack Obama’s health care overhaul even if the law fails to survive Supreme Court scrutiny later this month.

UnitedHealth Group, Humana and Aetna all said Monday that they will continue to cover preventive care such as immunizations and screenings without requiring patients to pay a set fee called a co-payment.

They also said they’d still cover adult children up to age 26 through their parents’ insurance plans. Additionally, they all pledged to continue to offer a simple process for patients who want to appeal when their health insurance claims have been denied.

WellPoint, the nation’s second largest insurer behind UnitedHealth, said it will announce its plans after the Supreme Court’s ruling. The company runs Blue Cross Blue Shield plans in several states.

The announcements come after insurers initially fought to block passage of the overhaul, which aims to provide coverage for millions of uninsured people. Challenges from states and other groups opposed to the law, which was passed in 2010, made their way to the Supreme Court. Justices are expected to rule later this month on whether to uphold the law or strike down parts or all of it.

Bob Laszewski, a consultant in the insurance industry, said insurers have probably added about 3 percent to a patient’s bill for the early provisions, depending on the type of coverage. As a result, he said it makes sense for insurers to keep the early provisions because if they didn’t, customers probably would expect a corresponding drop in the premiums they have to pay.