What are the 3 phases of the menstrual cycle?

• A. Follicular: estrogen surge causes LH & FSH to increase; Ovulatory: LH surge triggers ovulation; Luteal: start of ovulation begins, progesterone dominant
• B. Menstrual, Proliferative, Secretory
• C. Early, Mid, Late
• D. Menses, Ovulation, Implantation

Answer: (A)

The three phases come from the ovarian cycle: follicular, ovulatory, and luteal. In the follicular phase, FSH stimulates growth of ovarian follicles and estrogen is produced, driving proliferation of the endometrium. As estrogen rises to a high level, it triggers a surge in LH that leads to ovulation—the release of the oocyte from the dominant follicle. After ovulation, the luteal phase begins as the ruptured follicle becomes the corpus luteum, which secretes progesterone (with some estrogen). Progesterone maintains the endometrium in a secretory state to prepare for possible implantation. If fertilization does not occur, the corpus luteum regresses, progesterone and estrogen fall, and menses begins.

Note: Some sources describe the endometrial cycle as menstrual, proliferative, and secretory, which is a uterus-focused perspective, while the three ovarian-cycle phases are follicular, ovulatory, and luteal.