Composed Nutrition February 24, 2021 BIRTH CONTROL 9 Reasons for Hair Loss After Birth Control Composed Nutrition February 24, 2021 BIRTH CONTROL It is important to understand the 4 phases of the entire menstrual and what is going on in each one. The luteal phase is the last phase of the cycle. Learning about what is the luteal phase can help you understand your body and your hormones better.