Part 4/10:
- These hormones act on the ovaries, prompting the production of estrogen (mainly estradiol) and progesterone.
During the menstrual cycle, estrogen levels rise and fall, with notable peaks (spikes) followed by declines, leading to ovulation and the preparation of the uterus for potential pregnancy. Progesterone remains relatively low initially but rises after ovulation, stabilizing the endometrial lining. If pregnancy does not occur, progesterone and estrogen levels decline sharply, leading to menstruation.