Usage: 2 forms in 3 verses
Form Translated As     In Verse(s)
πρωτοτοκούσησ one giving birth for the first time LXX.Jer.4.31
πρωτοτοκούσασ having given birth for the first time LXX.1Sam.6.7LXX.1Sam.6.10

Liddell-Scott-Jones

πρωτοτοκέω (prōtotokeō) to give birth first time G:V

πρωτοτοκέω-έω,

bear one's first-born,[LXX]

LSJ Scripture Refs: LXX.1Kgs.6.7