Genesis 16:2

16:2 So Sarai said to Abram, “Since the Lord has prevented me from having children, have sexual relations with my servant. Perhaps I can have a family by her.” Abram did what Sarai told him.

Genesis 16:4

16:4 He had sexual relations with Hagar, and she became pregnant. Once Hagar realized she was pregnant, she despised Sarai.