From the Campaign Finance Institute:
The year 2018 saw a record number of women candidates competing in major party primary elections*, with another record number making it through to next week's general election. An analysis by the Campaign Finance Institute of pre-general election reports from the Federal Election Commission (FEC) shows that these candidates have been very successful in raising funds for the general election, especially in competitive races.
As a result, it is likely that the next Congress will set yet another record, for the number of women members. Currently there are eighty-four female members of the House. In next week's election, eighty-two races have female candidates whose elections are considered to be safe or likely. This includes sixty-nine incumbents and thirteen open seat candidates. Thirty-four competitive races feature a female running against a male. In these competitive incumbent/challenger or open seat races, women are outraising their male opponents, on average, by more than $500,000 each ($3.67 to $3.13 million).
Female House Incumbents
Nearly all female incumbents up for re-election in the House are in safe seats or considered likely to hold their seats. Only three races featuring a female incumbent and male challenger are expected to be competitive. Two of the three women are outraising their challengers. In the third, a male Democratic challenger is outraising the female Republican incumbent.
House Challengers and Open Seat Races
A clearer picture of how female candidates are competing this year can be seen by examining the thirty-one races that feature a female v. male candidate, and that are also expected to be competitive (open seats or female challenger). We count races as competitive if either the Cook Political Report or Inside Elections rates them as "Tossup" or "Lean". These key races show that female candidates are not only holding their own, but outraising their male counterparts. In twenty of the thirty-one races, the female candidate has raised more money through the pre-general election period than her male opponent (See Table 1).
As always the Senate is difficult to deal with in averages due to the small number of candidates. The Senate currently has twenty-three female Senators, the most in the history of the Senate . Two of those Senators are considered to be in competitive races, Heidi Heitkamp (ND-D) and Claire McCaskill (MO-D). Additionally, there are two women non-incumbents facing male opponents in competitive races, Jacky Rosen in Nevada (Heller-R) and Marsha Blackburn in Tennessee (Open-R). Two women were recently appointed to fill in for men who resigned and now face election to keep the seat. In Mississippi, Cindy Hyde-Smith (R) was appointed in April of this year to replace Thad Cochran. She is running against two male opponents. In Minnesota Tina Flint-Smith (D) replaced Al Franken. She is running against another female. Arizona's open seat race also has two women running to fill a seat being vacated by a man. Financially, Blackburn is the only female candidate on this list who is not outraising her male opponent; most of the others enjoy healthy fundraising advantages. Depending on the outcome of these races the Senate could lose as many as two women or gain as many as three.
* For an excellent report on female candidates in the primaries, see Grace Haley and Doug Weber, "Women's Success Defines 2018 Primaries", Sept. 26, 2018. Center for Responsive Politics. https://www.opensecrets.org/news/2018/09/womens-success-defines-2018-primaries/