WASHINGTON – A holdout no more, Sen. Ben Nelson agreed Saturday to provide the 60th and deciding vote for Senate passage of sweeping health care legislation, capping a year of struggle and a final burst of deadline bargaining.

Nelson, D-Neb., said he made his decision after winning fresh concessions to limit the availability of abortions in insurance sold in newly created exchanges, as well as tens of million in federal Medicaid funds for his home state.

“I know this is hard for some of my colleagues to accept and I appreciate their right to disagree. But I would not have voted for this bill without these provisions,” he said at a news conference in the Capitol.

He also noted he had successfully fended off attempts to provide for a government-run insurance option to compete with private insurers.

One Democratic official said an analysis by the Congressional Budget Office to be released later Saturday would estimate a deficit savings of more than $130 billion over 10 years, and the possibility of much more in the subsequent decade.

Forecasters said the bill would expand coverage to roughly 94 percent of eligible Americans under age 65, a total that excludes illegal immigrants. The official who described the conclusions spoke on condition of anonymity, saying he lacked authorization to pre-empt the release of the report.

With Nelson’s decision, President Barack Obama’s Senate allies appear on track to pass the legislation by Christmas, overcoming Republican opposition and a swirling early winter snowstorm.

At its core, the measure is designed to spread coverage to tens of millions who lack it, while banning insurance company practices such as denial of coverage on the basis of pre-existing medical conditions. The White House also wants the legislation that eventually clears Congress to slow the rate of growth in national medical spending overall. The House passed its version of the legislation last month, and final compromise talks are expected quickly.

Nelson disclosed his decision as Majority leader Harry Reid unveiled a final series of changes designed to solidify support.

The legislation includes new limits designed to limit insurance company profits and overhead, by requiring them to spend 80 percent of their premium income on medical care for individual insurance policies, and 85 percent for group policies. The industry says such a limitation is unnecessary because profits generally are in the single digits.

The estimated 30 million Americans purchasing coverage through new insurance exchanges would have the option of signing up for national plans overseen by the same office that manages health coverage for federal employees and members of Congress. Those plans would be privately owned, but operated on a nonprofit basis, as many Blue Cross Blue Shield plans are now.

The option amounts to a consolation prize for liberals, who failed to include a government-run alternative.

Additionally, insurance companies would be barred immediately from denying coverage to children because of a pre-existing health condition. The prohibition on denial of coverage for adults would not take effect in the Senate bill until 2014, a disappointment for consumer advocates.