The majority of research on the transition to parenthood has found that as couples become parents, they are experiencing a rapid and dramatic change in their family life and at risk of experiencing postpartum depression while they are unable to adapt to this stress. The intimate relationships also need to be readjusted after the baby was born. The goal of this article is to review the literature on postpartum depression for new parents and the changes in the couple relationship after the child was born, and to understand the mental health of new parents and their relationship adjustment. The suggestions for future researches and mental health professionals were discussed.