Conservative women were nearing a historic level of representation in the House, more than doubling the number of female Republican incumbents in the chamber as they scored key upsets in battlegrounds across the country and beat back Democratic challengers flush with cash.

Republicans were celebrating their success at chipping away at Democrats’ House majority and feeling increasingly confident of maintaining control of the Senate. By Wednesday evening, they had elected 22 women and were on track to have the highest number of them serving in their congressional ranks, surpassing the previous record of 25 women elected in 2004.

Those wins came as Republicans fought to protect female incumbents in the Senate, where Joni Ernst of Iowa prevailed in her competitive race, Kelly Loeffler advanced to a runoff in Georgia, and Susan Collins won a decisive victory in her re-election race in Maine. Cynthia Lummis, a former House lawmaker, became the first Republican woman to represent Wyoming in the Senate, replacing the retiring incumbent, Senator Michael B. Enzi.