When Yahweh saw that Leah [was] unloved he opened her womb, but Rachel [was] barren.
References for Genesis 29:31
Then Leah conceived and gave birth to a son, and she called his name Reuben, for she said, "Because Yahweh has noticed my misery, that I [am] unloved. Now my husband will love me."
And she conceived again and gave birth to a son. And she said, "[It is] because Yahweh has heard that I [am] unloved that he gave me this [son] also." And she called his name Simeon.
And she conceived again and gave birth to a son. Then she said, "Now this time my husband will be joined to me, for I have borne him three sons." Therefore, she called his name Levi.
And she conceived again and gave birth to a son. And she said, "This time I will praise Yahweh." Therefore she called his name Judah. And she ceased bearing children.