Menstrual Cycle Phases and Infectious Diseases
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Menstrual Cycle Phases
- Proliferative phase: The mucous membrane of the uterus, called the endometrium, builds up. This phase is initiated by estrogens (produced by the ovaries). It lasts approximately 11 days.
- Luteal phase: The endometrium reaches its maximum thickness and prepares to receive and nourish an embryo. This phase is initiated by progesterone (released by the corpus luteum of the ovaries). It lasts approximately 12 days, until the hormone ceases production. If an embryo is present (if an egg has been fertilized), the corpus luteum continues to secrete progesterone.
- Menstruation: This phase only occurs when there is no embryo. The ovaries secrete significantly lower levels of hormones. Consequently, the endometrium, now quite thick