Lawmakers approved a short-term extension of the nation’s primary autism law, but the path to renewing the measure, which includes nearly $2 billion for the developmental disability, could be rockier than expected.

Disability advocates have been pushing Congress for months to renew the law known as the Autism Collaboration, Accountability, Research, Education and Support, or Autism CARES, Act before it expired at the end of September. The U.S. House of Representatives voted to re-up the measure, but the Senate failed to act.

Rather than let the law sunset, however, Congress included an extension of the Autism CARES Act in a broad short-term spending bill signed into law last week to avert a government shutdown. The measure will maintain funding for federal programs — including those authorized by the Autism CARES Act — through Dec. 20.

Now, it’s expected that further consideration of the autism law will wait until Congress reconvenes after the November election and it’s unclear how things will play out at that point.

Disability advocates say that Sen. Rand Paul, R-Ky., and possibly one other senator have placed a hold on the autism bill. A hold offers lawmakers the opportunity to prevent a vote while they discuss their issues with a particular piece of legislation.

It’s not known what concerns prompted the Senate hold and representatives for Paul did not respond to questions about the matter.

“We are concerned about the holds and hope they can be overcome when the Senate returns in November,” said Kim Musheno, vice president of public policy at the Autism Society of America. “Of course we wish it had passed before the Senate recessed; however, the law has such strong and overwhelming bipartisan support, so I think (it) will ultimately prevail.”

The version of the Autism CARES Act that passed the House last month would allocate more than $1.95 billion over the next five years for research, prevalence tracking, screening, professional training and other government activities related to autism.

In addition to extending many provisions of the existing Autism CARES Act, the new bill would direct the National Institutes of Health to ensure that research reflects the full range of cognitive, communicative, behavioral and adaptive functioning needs of those on the spectrum. The legislation calls for an increase in the number of NIH Centers of Excellence, it would require the NIH to produce an annual budget plan for autism research and it includes efforts to promote the adoption of assistive communication.

What’s more, the bill would require a government report on ways to increase the number of developmental behavioral pediatricians and another looking at youth aging out of school.

Going forward, advocates say they are working to make sure the law, which enjoys broad bipartisan support, doesn’t hit more bumps later this year.

“While the Senate’s early adjournment includes a temporary extension of programs under the Autism CARES Act protecting the autism community from disruption of essential initiatives, whether the 1 in 36 autistic children and 1 in 45 adults in the U.S. will continue to receive care and support for a diverse range of evolving needs is dependent on what happens when the Senate reconvenes in November,” said Stuart Spielman, senior vice president of advocacy at Autism Speaks. “The authorization and appropriation for autism activities around developmental disabilities surveillance and research; autism training, early detection and intervention; and the Interagency Autism Coordinating Committee has not lapsed, but now is the time for advocates to make their voices heard encouraging their senators to ensure the Autism CARES Act before its new expiration date in December.”