What complaint did Sarai bring to Abram, and how did Abram respond?

Sarai complained that it was Abram's fault that Hagar despised her, and Abram told Sarai to do what she thought best with Hagar.

How did Sarai treat Hagar after Hagar conceived, and what did Hagar do?

Sarai treated Hagar harshly, and Hagar fled.