1 The disjunctive clause signals the beginning of a new episode in the story.
2 On the cultural background of the story of Sarai’s childlessness see J. Van Seters, “The Problem of Childlessness in Near Eastern Law and the Patriarchs of Israel,” 87 (1968): 401–8.
3 The Hebrew term שִׁפְחָה (shifkhah, translated “servant” here and in vv. 2, 3, 5, 6, and 8) refers to a menial female servant.
4 The passage records the birth of Ishmael to Abram through an Egyptian woman. The story illustrates the limits of Abram’s faith as he tries to obtain a son through social custom. The barrenness of Sarai poses a challenge to Abram’s faith, just as the famine did in chap. 12. As in chap. 12, an Egyptian figures prominently. (Perhaps Hagar was obtained as a slave during Abram’s stay in Egypt.)

In other versions

Now Sarai, Abram’s wife, had borne him no children. She had a female Egyptian servant whose name was Hagar.

Now Sarai, Abram’s wife, had borne him no children. But she had an Egyptian slave named Hagar;

Abram’s wife, Sarai, had not borne any children for him, but she owned an Egyptian slave named Hagar.

Now Sarai, Abram’s wife, had not been able to bear children for him. But she had an Egyptian servant named Hagar.

Now Sarai, the wife of Abram, had borne him no children. And she had an Egyptian female slave, and her name was Hagar.

Now Sarai Abram’s wife bare him no children: and she had an handmaid, an Egyptian, whose name was Hagar.

Public Domain