The text highlights two results, both of which are the work of God. First, God dealt well with the midwives.
He ensured that Pharaoh would believe their answer, protecting them from harm and allowing them to continue their work. In addition, as recounted in Exodus 1:21, God gave them families.
Second, the people multiplied and grew very strong.
Through the midwives, God frustrated Pharaoh’s schemes. Even this latest attack cannot slow Israel’s growth (Exodus 1:7).
20 So God dealt well with the midwives. And the people multiplied and grew very strong.