Phases of the Menstrual Cycle and Hormonal Effects

Phases of the Menstrual Cycle

Menstrual Phase (Day 1-5)

• Description: This phase involves the shedding of the lining of the uterus.

• Hormonal Activity: Both estrogen and progesterone are low.

Follicular Phase (Days 1-13)

• Description: This phase begins after the menstrual phase, during which estrogen levels increase significantly while progesterone levels remain low.

• Function: The increasing estrogen prepares the egg for ovulation.

Ovulation (Day 14)

• Key Event: The ovary releases a prepared and mature egg.

• Hormonal Change: There is an increase in luteinizing hormone (LH), which is essential for pregnancy.

• Hormonal Peak: Estrogen reaches its peak during this phase, indicating optimal conditions for fertilization.

Luteal Phase (Days 15-28)

• Hormonal Changes: Progesterone levels increase, leading to the thickening of the uterine lining in preparation for a potential pregnancy.

• If Fertilization Does Not Occur: Hormone levels decline, which can lead to premenstrual syndrome (PMS) symptoms during this phase.