Losing Isaiah (1995)

Khaila Richards, a crack-addicted single mother, accidentally leaves her baby in a dumpster while high and returns the next day in a panic to find he is missing. In reality, the baby has been adopted by a warm-hearted social worker, Margaret Lewin, and her husband, Charles. Years later, Khaila has gone through rehab and holds a steady job. After learning that her child is still alive, she challenges Margaret for the custody.

Source: TMDb