I think it's split, more or less, equally.
I think most women - more than half - are not in favor of abortion on demand at any stage of the pregnancy.
I think - maybe - most women are in favor of some sort of abortion at a very early stage in the pregnancy.
This is why this ruling is a good thing for the country - it spawns discussion and can lead to a compromise at a more local level. If the US Congress was doing it's job, it would craft a reasonable national compromise but, as everything else, that is impossible in the current environment.