Zilpah
Zilpah, the handmaiden of Leah, bore two sons to Jacob, named Asher and Gad.
It was the custom of those times if the wife was barren. Then a another woman would bare children for her.
Zilpah was not from the family of Laban but a servant in the extended household.
Zilpah in Hebrew means Drooping.
Background Reading:
Zilpah
9 When Leah saw that she had stopped having children, she took her maidservant Zilpah and gave her to Jacob as a wife. 10Leah's servant Zilpah bore Jacob a son. 11 Then Leah said, "What good fortune!" So she named him Gad.
12 Leah's servant Zilpah bore Jacob a second son.13
Then
Leah said, "How happy I am! The women will call me happy." So she named
him Asher.
Genesis 30:9-12