I just thought of something! The verse's beginning
HaNefilim hayu va'aretz bayamim hahem instead of
Vayehi hanefilim ba'aretz bayamim hahem *could* indicate that the verb is being used as a past perfect: "
There had been nefilim in those days . . .
and after that" etc. The Oral Tradition and the Great Commentators find meaning when a verb form seems unusual or not what it would be ordinarily. For example, because the fourth chapter of Genesis begins
VeHa'Adam yada` 'et Chavvah 'Ishto instead of
Yayeda` Ha'Adam 'et Chavvah 'ishto they teach that this means that Cain and Abel had already been born in the Garden rather than their births taking place where they are first mentioned chronologically in the narrative. A similar argument has been made to suggest that Jacob had
already fed his brother Esau before he bought his birthright, ie, that he didn't essentially force the birthright out of a hungry man. This is because Genesis 25: 34 begins
VeYa`aqov natan ("and Jacob had *already given*") rather than
Vayitten Ya`aqov ("*then* [after Esau sold him his birthright] Jacob gave him"). You see why the Bible can't really be translated, folks?
The only problem with this is why is the word nefilim in the verse with the definite article (ha = "the")? Why does it said that there had been THE abortions/miscarriages instead of just abortions/miscarriages? HaNefilim is definitely referring to something specific.