Hagar's return to Sarai and Abram is implict. You can make this more explicit: "So Hagar went back and gave birth." (See: [[rc://en/ta/man/translate/figs-explicit]]).
"named his son by Hagar" or "named his and Hagar's son"
## Abram was ##
This introduces background information about Abram's age when these things happened. Your language may have a special way to mark background information. (See: [[rc://en/ta/man/translate/writing-background]])
## bore Ishmael to Abram ##
This means "gave birth to Abram's son, Ishmael." The focus is on Abram having a son.