Republicans were fighting early Wednesday to keep their five-seat majority in Pennsylvania's U.S. House delegation, an edge to be decided by a suburban Philadelphia district where the freshman GOP incumbent was trailing against his Democratic challenger.

The state's other 15 House incumbents won re-election as Republicans held on to two open seats and Democrats a third.

With 75 percent of precincts reporting in the 6th Congressional District in Philadelphia's western suburbs, Democratic challenger Lois Murphy was leading Republican freshman Rep. Jim Gerlach, 52 percent to 48 percent.

Murphy, an ally of Democratic Gov. Ed Rendell, was seeking to capture one of two GOP-held seats that were viewed as highly vulnerable to switching parties.

Republicans held on to the other vulnerable seat, in the open 8th District seat north of Philadelphia, where GOP Bucks County Commissioner Mike Fitzpatrick defeated Democrat Ginny Schrader, who has never held elected office. The seat initially was believed to be an easy GOP keeper until Republican U.S. Rep. Jim Greenwood announced in August he would retire at the end this year.

With 99 percent of precincts reporting, Fitzpatrick prevailed with 55 percent to Schrader's 43 percent.

Democrats held their ground by winning the open 13th District in parts of northeast Philadelphia and Montgomery County -- a nasty race marked by name-calling and finger-pointing between the candidates.

The battle for that seat, being vacated by retiring Democratic Rep. Joe Hoeffel, was the most competitive of 11 House contests in the country pitting two women against each other. Democratic state Sen. Allyson Y. Schwartz defeated Republican Melissa Brown, an eye surgeon making her third bid for the seat. With 99 percent of precincts reporting, Schwartz had 56 percent to Brown's 41 percent.

In the campaign's closing days, Brown attacked Schwartz as a "radical" liberal and Schwartz called Brown "sleazy" for the way she's campaigned for federal public housing reforms.

Local roots were a top issue in the third open seat -- the race to succeed retiring GOP Rep. Pat Toomey in the Lehigh Valley's 15th District. With 83 percent of precincts reporting, hometown candidate Republican state Sen. Charlie Dent defeated district newcomer Democratic businessman Joe Driscoll, 59 percent to 39 percent.

In another high-profile race, in central Pennsylvania's 17th Congressional District, Democratic Rep. Tim Holden scored a seventh term against Republican attorney Scott Paterno, son of Penn State football coach Joe Paterno. With 83 percent of precincts reporting, Holden had 57 percent to Paterno's 40 percent. Republicans outnumber Democrats by a 3-2 margin in the district.