Pediatric coverage benefits offered through the Affordable Care Act’s exchange plans vary widely across the country – and so far, there is little data to show whether or not these variations are creating gaps in the children’s care here.

California children’s advocates have asked for more data from Covered California, the state’s insurance marketplace. They’ll use that information to identify any coverage gaps that can be sealed when California has the opportunity to revisit the requirements for children’s care, likely in 2016.

Already, there’s one obvious hole in the state’s required coverage for pediatric plans: hearing aids, which are covered for children on Medi-Cal, the public insurance plan for low-income people, said Michael Odeh, the associate director of health policy for Children Now, an Oakland-based advocacy group.

Kathleen Hamilton of the Santa Monica-based nonprofit The Children’s Partnership said she’s interested in seeing if these plans share the same dental challenges plaguing young Medi-Cal patients, more than half of whom did not receive dental care through the program in 2013, according to a state audit.

A coalition of children’s and consumer advocacy groups, including Children Now and The Children’s Partnership, sent a letter to Covered California officials in March requesting information on how well those plans are serving the 77,000 children they estimate are enrolled.

“As Covered California continues to implement its second year of enrollment, we appreciate this opportunity to stress the importance of examining the enrollment and access experiences of children and their families,” according to the letter. “Although children comprise less than six percent of the Covered California population, it is important that the California Health Benefit Exchange Board has the necessary information to understand how children are served by the Exchange.”

Those organizations sought data on how many individuals under age 18 are receiving coverage, as well as a breakdown by age group. They also asked for geographic data, the types of plans selected, and how many participants were receiving subsidies. And, they asked how the board would access the quality of enrollees’ experiences moving forward.

“It has been noted that some plans offered by Covered California may have narrow provider networks that may inhibit a child from seeing an appropriate provider or specialist in a timely manner,” advocates wrote. “Access to pediatric and child-serving providers is particularly critical for children, for whom preventive care services, immunizations, and regular and timely developmental and behavioral health screenings can significantly shape their future health.”

Even though the ACA requires all exchange plans to offer pediatric coverage as an essential benefit, states decide the extent of that coverage by choosing a benchmark plan. The benchmark plan in California is a Kaiser HMO plan, and policies sold on the exchange must cover the benefits offered in that plan. Other states may choose benchmark plans with fewer (or more) benefits. As a result, researchers have found wide geographic variation nationwide on everything from coverage for congenital defects to treatment for autism spectrum disorder.

“The Affordable Care Act offers great promise for kids, but we are concerned that its intended benefits are not fully realized for children,” according to a recent Health Affairs study, which described “patchy pediatric coverage” nationwide.

Despite their concerns about monitoring access and quality of care, advocacy groups in California say they’re happy with the exchange plans’ benefits so far.

The addition of dental coverage embedded in the exchange plans this year was a victory for young patients, children’s proponents say. And, they’ve looked into Applied Behavior Analysis (ABA) coverage, a treatment for autism, and been pleased that kids covered by exchange plans are receiving that therapy– something the Health Affairs report highlighted as an issue in states across the country.

Karen Fessel, founder of the California nonprofit Autism Health Insurance Project, said she hasn’t seen a significant difference in plan coverage for children with autism who have private insurance plans vs. exchange plans. California is one 24 states plus Washington D.C. that requires insurance carriers to sell policies on the exchanges that cover behavioral health treatments such as ABA, according to that group.

Anthony Wright of Health Access, a consumer advocacy group, adds that access to care is likely easier for children with Covered California plans as opposed to Medi-Cal, the plan that insures most the children in the state. Covered California plans resemble private insurance when it comes to provider reimbursement rates, whereas Medi-Cal’s low reimbursement rates leads to access problems since many providers chose not to take those patients, or limit how many they see.

Experts predict, however, that narrow provider networks will become a bigger concern for all types of health coverage, on the exchanges and beyond.

“There are network adequacy issues overall with Covered California and pediatrics isn’t immune,” said Abbi Coursolle, a staff attorney with the National Health Law Program in Los Angeles.

The term narrow network refers to plans in which participants have limited choices on which doctors or hospitals they can use. Some plans don’t pay for visits outside their networks while others might charge higher co-payments for an “out-of-network” visit. As part of cost-containing efforts, narrow networks gained ground even before the Affordable Care Act. But health experts say reform helped fuel their growth.

Since exchange plans are so heavily regulated, the formation of provider networks for both adults and pediatric clients are one of the only areas where plans have discretion, explained Ben Handel, an assistant professor of economics at the University of California Berkeley, who researches health exchanges.

“As a result, you’ve seen a lot of variation in networks,” he said. “Some insurers have broad ones, but a lot have narrow networks with restricted providers.”

Narrow network complaints have spurred lawsuits in California, including one against health insurance giant Anthem Blue Cross, which accused the company of misrepresenting the size of its provider networks. Similar lawsuits were also filed last year against Cigna and Blue Shield of California. In response to those and other complaints, the state legislature now requires health plans to provide annual reports to the California Department of Managed Health Care about their provider networks.

On a national level, the authors of the recent Health Affairs study pointed to a series of policy steps that could improve health coverage for young patients on exchange plans. They want to prohibit pediatric treatment limits and exclusions and define a nationwide pediatric standard instead of relying on individual states to define care.

Those steps could help eliminate some of the variation they found nationwide for children’s plans, such as congenital defects treatments, coverage for autism spectrum disorder and hearing aids. Researchers also found state-by-state differences for services that were specifically excluded. For example, 13 states exclude services for children with learning disabilities and ten exclude speech therapy for developmental delays, stuttering or both, the report found.

In California, children’s health advocates are hoping they can gather and evaluate adequate data before the state confirms its benchmark plan for the 2017 coverage year. Depending on the findings, advocates say they could request specific requirements for pediatric benefits to be included in that plan.

“There will be opportunity to revisit the benchmarks and I think we’ll see some legislation on the state level,” Odeh said. “The conversation is underway.”

Even though the numbers of children covered under California exchange plans are few, experts predict they will increase, underscoring the importance of understanding these plans and strengthening any gaps.

“We know the cost of employer-sponsored coverage is increasing for employees and their families,” Odeh said. “I can see more people turning to the marketplace.”