Connecticut Children’s Medical Center and Anthem Blue Cross and Blue Shield had discussions Tuesday but did not reach an agreement on a new contract that would lead the hospital to return to the insurer’s network. The two sides are expected to continue talks throughout the week, according to a hospital spokeswoman.

The Hartford children’s hospital let its contract with Anthem expire as of midnight Monday, saying the insurer would not provide adequate rate increases. Anthem said it had offered to raise its rates, but that the hospital was looking for commercial insurers to help cover shortfalls in payments from government insurance programs.

Children covered by Anthem can still receive care at the hospital, but their families could be required to pay higher rates because the hospital is considered out-of-network. Connecticut Children’s Specialty Group also let its contract with Anthem expire.

Anthem is the largest health insurer in the state and covers about a quarter of the patients at Connecticut Children’s. The children’s hospital also runs the pediatric unit at St. Mary’s Hospital in Waterbury and the neonatal intensive care unit at UConn’s John Dempsey Hospital.

State Healthcare Advocate Victoria Veltri said her office received 50 calls about the issue Monday, many from families of children getting care at the hospital. One caller had a child who had brain surgery at Connecticut Children’s and was scheduled to have a follow up.

“His mom is very worried about whether he’s going to get in to his doctor,” Veltri said. “And because he has a condition that would require a lot of care, she has legitimate concerns as to where or if her child is going to get continuation of care.”

Veltri said in that case, her office will make the argument to Anthem that it should cover the child’s care as if the hospital were in-network.

Anthem has already approved in-network rates for some cases, she added. “They don’t want their members to be put at risk by interrupting their care,” Veltri said.

Despite the contract expiration, emergency room care will still be covered as if it is in-network. Newborns in the neonatal intensive care units at Connecticut Children’s or Dempsey as of Monday will remain covered on an in-network basis until being discharged, as will children who are inpatients at Connecticut Children’s or the St. Mary’s pediatrics unit.

In some other cases, patients should be able to continue to receive care at in-network rates, Veltri said, although it could require working with Anthem, either directly or through Veltri’s office. Those cases include patients already getting care, such as cancer treatment, at the hospital, or those who need a particular procedure or type of treatment that is only done at Connecticut Children’s.

An Anthem spokesman did not return a call for comment Tuesday.

The Office of the Healthcare Advocate can be reached at 1-866-HMO-4446 or Healthcare.advocate@ct.gov.