In the average poll since June, Democrats are leading among women by an average 20-percentage point margin compared to trailing among men by 6 points. If this holds, this would be the largest margin that Democrats would win women by in a midterm election since at least 1958. [Note: ANES polling is not made to match the actual result like the exit poll is. I have adjusted it (and therefore the gender crosstab) so that the overall ANES congressional poll result matches the final outcome in each year.)
The two best years for Democrats before this year were the 1974 and 1982 midterms when Democrats won among women by about 14 and 17 points respectively. House Democrats are also doing considerably better than in 2014 when they won among women by 4 points, and Democrats this year are doing better than Clinton did in 2016 when she won women by 13 points.
Of course, it could be argued that some of Trump’s actions that alienate women voters could attract more men voters. Republicans are still leading with men in the polling, even if that lead is down from 2016. That is, it’s unclear that Republicans doing particularly poorly among women is necessarily hurting them among the larger electorate because the effect may be canceled out by doing better with men than otherwise might be expected.