Roughly 2 million Massachusetts residents, including more than 700,000 people 20 and younger, depend on the federal health insurance program for the poor. But tens of thousands could lose coverage as Congress races to pass legislation — perhaps by the end of the week — that would slash Medicaid spending.

About 250,000 people in Massachusetts would lose coverage under a version of the legislation passed by the House, Governor Maura Healey estimated. A Senate bill that passed with a tie-breaking vote by Vice President JD Vance on Tuesday appears more draconian, state officials said. The legislation now goes back to the House for a final vote.

The Senate plan would increase the number of uninsured in the country by almost 12 million, primarily through Medicaid cuts, according to the Congressional Budget Office. The House bill would eliminate health coverage for about 11 million people nationwide.

Health care providers said the impact of the cuts would reach beyond those covered by Medicaid. In Massachusetts, hospitals would lose a combined $364 million a year, according to one analysis, shaking the foundation of a health care system already strained by the collapse of Steward Health Care last year, the closing of two of its hospitals, and costs of integrating six others into new health networks.

“If the Republicans impose additional cuts, then we could see more Massachusetts hospitals stagger and fall,” said Senator Elizabeth Warren, a Cambridge Democrat.

Massachusetts is among many states that rely on provider assessments, the state Health and Hospital Association said, which allows them to use revenue from taxes on health care providers to fund Medicaid expenses. The Senate bill would reduce states’ ability to generate money through these taxes.

From teaching hospitals to community health centers, from Boston to the state’s rural corners, cuts to Medicaid could translate into more expensive care, reduced services, and longer waits for everyone, medical practitioners and policy experts said. Hundreds of thousands of people in Massachusetts could find the places they turn to for medical care dramatically diminished — or gone.

UMass Memorial Health in Worcester could be forced to cut medical services that are money-losers: pediatrics, obstetrics, psychiatry, and primary care, said Dr. Eric Dickson, the system’s chief executive. Or it might have to impose a double-digit increase on what it charges commercial insurers — increases likely to be passed on to patients in the form of higher insurance premiums.

Diana Cortes got a kiss from her daughter, Layla, 3 as her sister Arya, looks on. Layla had a liver transplant in June 2023.John Tlumacki/Globe Staff

About two-thirds of patients at UMass Memorial use government insurance, about one-quarter of them covered by Medicaid. Dickson estimated his health system would lose $100 million to $300 million if the Medicaid cuts go through.

“This will be the single worst thing that ever happened to UMass Memorial,” said Dickson, who noted his hospital was already grappling with a $100 million operating loss this year.

Also at risk are Massachusetts’ 50 community health centers, which provide primary medical, dental, and mental health care to about 1 million people statewide.

An average of 31 percent of community health centers’ money comes through Medicaid, said Michael Curry, chief executive of the Massachusetts League of Community Health Centers. Some centers have much larger Medicaid patient populations.

By taking away coverage from people, Curry said, the cuts will drive up health costs as patients put off care for chronic diseases and forgo screening for potentially serious illnesses — requiring more expensive care when their health spirals into a crisis.

Curry’s mantra: “Pay now or pay greater later.”

On a recent Friday, patients, from children with young mothers to old men with walkers, filled every seat in Brockton Neighborhood Health Center’s waiting rooms. A slow day, staff remarked.

About half the health center’s 40,000 patients are enrolled in the state’s Medicaid program, placing it among the community health centers in the state most vulnerable to cuts.

One of the center’s busiest waiting areas helps people register for MassHealth or maintain their enrollment. Filling out paperwork, providing documentation about income, and even figuring out where to mail the forms can prove challenging for many people.

One slip, such as mailing forms to the wrong address, can cost someone their benefits.

Adding enrollment and eligibility requirements, as both the House and Senate would do, would increase the chances of errors and loss of coverage, patient advocates said. For example, advocates said, the problem with work requirements isn’t the work — most Medicaid recipients hold jobs, often more than one — but the additional forms and documentation.

Losing a pay stub or leaving the wrong line blank could lead to a cutoff in benefits.

“They’re weaponizing the bureaucracy of the program to make it harder for people to get coverage,” said Katherine Hempstead, senior policy officer at the Robert Wood Johnson Foundation, a philanthropy focused on health.

The added bureaucracy would also make it harder for the Brockton health center, which would need to hire additional staff to help patients meet new requirements, said Maria Celli, the center’s chief executive. Already struggling with a $3 million budget deficit, the center would likely have to reduce medical services to cover the added costs.

“We really have not had a chance to catch our breaths as a staff collectively since before COVID,” said Celli. “We are closing that gap while facing this potential storm.”

Maria Celli is CEO of the Brockton Neighborhood Health Center. About half the center’s patients are covered by Medicaid, making the center vulnerable to cuts.Jonathan Wiggs/Globe Staff

On the other side of the state, drastic Medicaid cuts could hobble health care in rural communities. About one-third of the 9,000 patients at Community Health Center of Franklin County rely on Medicaid, said the health center’s chief executive, Dr. Allison van der Velden.

Those patients tend to be older, she said, and often need treatment for chronic illness. The health center’s funding has remained flat as the cost of care grows; it has operated in the red for years.

In December, it received $173,000 from the $12 million in state funding for health centers in financial distress.

“The threat of cuts to any of our revenue streams is pretty scary,” van der Velden said.

The health center would respond to reduced Medicaid revenue by cutting services, including transportation assistance. That kind of help is vital to older patients unable to drive the long distances typical in rural areas.

“Even people with some resources,” she said, “may not be able to drive over 100 miles” for medical care.

Hospitals and health centers serving populations that rely on Medicaid and Medicare, the health insurance program for the elderly, tend to struggle financially because government reimbursements are low — sometimes not enough to cover the costs of care.

Lawrence General Hospital has operated in the red for at least six consecutive years and each year submits about $12 million in claims to the state’s Health Safety Net fund for reimbursement of services provided to uninsured or underinsured patients. About three-quarters of patients at Lawrence General are covered by Medicaid or Medicare, said Diana Richardson, the hospital’s chief executive.

Richardson said cuts to Medicaid might force the hospital to focus its already limited resources on emergency and acute care at the expense of primary care and preventative medicine, such as colonoscopies and other screening tests.

“It would be pretty devastating if the federal plans go through as written,” Richardson said.

Nearly half of the patients from Massachusetts at Boston Children’s Hospital rely on Medicaid, according to Josh Greenberg, the hospital’s vice president of government relations.

“If you yank a whole bunch of money out of the Medicaid program, you are by definition putting children at risk,” he said. “It is the safety-net program for children, and it disproportionately covers children with complex medical conditions.”

One of them is Cortes’s daughter, Layla, who was diagnosed with a rare liver disease called biliary atresia as an infant. Layla spent nine months at Children’s waiting for a suitable liver to be transplanted, according to her mother. She became frail and skinny, and Cortes feared that she would die.

Without the surgery, said Cortes, “she would not be here today.”

On June 11 and 12, Children’s arranged for families of four patients from Massachusetts, Maine, Louisiana, and Oklahoma to visit Capitol Hill to lobby their states’ legislators to preserve Medicaid. Cortes, Layla, and Layla’s 5-year-old sister, Arya, were among them.

“To know that a lot of these families are going to be at risk for losing their child simply because of legislation,” said Cortes, “that doesn’t make any sense.”

Diana Cortes showed a photo taken while she and her daughters Layla and Arya visited Massachusetts Representative Lori Trahan in Washington. John Tlumacki/Globe Staff

Correction: This story has been updated to clarify that the 250,000 people who would lose health insurance under cuts approved by the House include some who obtain coverage through the Affordable Care Act and that the Community Health Center of Franklin County received only a portion of the $12 million in state funding for health centers in financial distress.

Jonathan Saltzman can be reached at jonathan.saltzman@globe.com. Jason Laughlin can be reached at jason.laughlin@globe.com. Follow him @jasmlaughlin. Jim Puzzanghera can be reached at jim.puzzanghera@globe.com. Follow him @JimPuzzanghera.