Sen. Susan Collins, R-Maine, signaled Thursday that she would need to see changes to a healthcare bill's draft introduced by Republicans in the Senate before offering her support, adding to the ranks of Republicans who already appear uncertain about the bill.

"I can't support a bill that's going to greatly increase premiums for our older Americans or out-of-pocket costs for those who aren't quite old enough for Medicare yet," Collins, a key centrist vote, said in an interview with NBC's "MTP Daily." "I cannot support a bill that is going to result in tens of millions of people losing their health insurance, and I cannot support a bill that's going to make such deep cuts in Medicaid that it's going to shift billions of dollars of costs to our state governments ... and to healthcare providers, such as rural hospitals, which would be faced with a great deal of uncompensated care."

"So it isn't any one factor," she continued. "I do care also about funding Planned Parenthood. It's all of those factors put together that will influence my decision."

Collins had introduced her own Obamacare replacement bill with Sen. Bill Cassidy, R-La., which would have allowed states to keep Obamacare or to structure their own coverage plans. The draft introduced in the Senate on Thursday would roll back Obamacare taxes, provide tax credits for people to buy private coverage and change the structure of Medicaid, ultimately resulting in reduced funding for the program, much of which covers people with disabilities, pregnant women and people in nursing homes.

Collins has said that she will offer an amendment that would allow funds for Planned Parenthood to continue. The GOP bill calls for federal family planning funds for services like cancer screenings, STD testing and birth control to be stripped from organizations that also provide abortions. Under the Hyde Amendment, federal taxpayer dollars are prohibited from going toward most abortions.

The bill's projections regarding coverage and budget items are set to be outlined next week by the Congressional Budget Office, which predicted that the House bill would result in 23 million more people being uninsured by 2026.

Asked by host Chuck Todd whether she could imagine enough amendments passing to fulfill the pledges she made, Collins replied: "It's going to be an open amendment process and I'm sure many of us are going to have amendments. In addition, I want to see that CBO analysis because I don't know the exact impact yet."

The Senate healthcare bill will be voted on through a measure known as reconciliation, which requires only a simple majority for passage. No Democrat is expected to vote for the bill, so Republicans cannot afford to lose more than two votes to pass the bill, assuming a tie-breaking vote by Vice President Mike Pence. Four conservative senators have already said they cannot support the bill as it is written because they say it does not do enough to lower premiums or undo Obamacare.