An effort to tie abortion restrictions to tax credits in a healthcare bill doesn't meet Senate rules according to the chamber's parlimentarian, two senators said on Wednesday.

Sen. Susan Collins, R-Maine, told reporters Wednesday she believes the tax credits didn't meet the rules for reconciliation, which is the process by which Republicans are using to try to pass a healthcare bill with a simple majority to avoid a Democratic filibuster. Sen. Thom Tillis, R-N.C. said the same.

"I believe that did not pass through the parliamentarian's review so I don't expect that," Collins told reporters.

Tillis indicated that Republicans were looking at other ways to include anti-abortion language in the bill.

"It would not be in the direct sense it was proposed in the House, but I think there are ways to address most of the concerns of members," he said.

If the senators are right about the judgment by the senate parliamentarian (which was not yet confirmed by leadership), it would complicate efforts by Republicans to craft a healthcare compromise that satisfies all of the party's ideological factions. The House-passed bill created a new set of tax credits for individuals to purchase insurance that included Hyde Amendment language, a spending rider that prohibits federal funding from going towards abortions.

If that is no longer allowed, it means that in order to include anti-abortion language that will be crucial to securing the votes of conservatives, Senate drafters will have to come up with a new way to introduce their tax credits, most likely by running them through an existing program that already includes Hyde langauge, or by tweaking the tax credits in Obamacare itself. Obamacare includes weaker anti-abortion language that is not satisfactory to social conservatives, and modifying those subsidies would also reinforce criticisms on the right that the healthcare bill is simply "Obamacare Lite."

Reconciliation bills carry a number of restrictions, such as that provisions must be primarily budgetary in nature. The Senate parliamentarian is tasked with advising the Senate on whether any part of the bill meets the reconciliation rules.

If a part of the bill does not, then it would have to be taken out, unless the presiding officer of the Senate (likely to be Vice President Mike Pence in this case) chooses to disregard the parliamentarian's advice and issue a contrary ruling. But Senate Majority Leader Mitch McConnell, R-Ky., has argued for deference to the parliamentarian, and it is unexpected that Pence would disregard her judgment.