Abortion remains a top sticking point for House Democrats as they try to pass a health care reform package later this week, and it may have just gotten more complicated.

Fox News has learned that Elaine Olsen, the mother-in-law of Rep. Bart Stupak (D-MI) passed away unexpectedly Sunday in Escanaba, Mich. 

His unexpected absence could profoundly impact the ongoing debate on abortion access encompassed in health care legislation.

Stupak signaled last week that unless the abortion impasse was bridged, he had enough votes to blow up the bill. Stupak and other Democrats who oppose abortion are calling for a “vote against using public funds for abortions.

Stupak is not expected to be in Washington this week.

A senior House leadership aide who didn’t wish to be identified indicated that Stupak’s absence wouldn’t hurt talks on the abortion issue.

But another key Democrat involved in the abortion discussions saw it differently. When asked if Stupak’s unavailability could impact the issue, the lawmaker responded “Yeah. Big time.”

House Democrats are now huddled behind closed doors working out what’s called a “manager’s amendment” to the 1,990-page health care reform bill. The manager’s amendment is the final alterations that are made to legislation before it hits the House floor.

When asked by reporters whether it was essential to solve the abortion question before introducing the manager’s amendment, Rep. Chris Van Hollen (D-MD) responded “not necessarily.”

Van Hollen serves as special assistant to House Speaker Nancy Pelosi (D-CA) and is intimately involved in all health care conversations. Van Hollen told reporters that the leadership could move ahead with the manager’s amendment and “work (abortion) out later.”

But others differed with Van Hollen.

“Obviously (abortion) has to be worked out before they pass the bill,” said Rep. Gerry Connolly (D-VA).

It’s illegal to use federal money to pay for abortions except in rare instances. Over the summer, Democratic leaders favored a provision that allowed people to use government money to purchase private health plans that could pay for abortions. But policyholders would have to use private money to pay for the actual procedure.

Still, Stupak and others argued that federal dollars shouldn’t be used at all to buy coverage that could potentially cover abortions.

Senior House sources indicate to Fox that the manager’s amendment is essentially complete and just needs to be written in parliamentary language. House leaders are pledging to post this final addendum to the health care bill online for three days before advancing the health care bill on the floor.

A throng of reporters accosted Pelosi outside her office Tuesday night, asking the speaker when she’d introduce the manager’s amendment.

“We’ll let you know when we’re ready to let you know,” Pelosi said cryptically.

Fox News' Chad Pergram contributed to this report.