What hormone is elevated during days 1-13 of the menstrual cycle?

• A. Estrogen
• B. Progesterone
• C. Follicle-stimulating hormone
• D. Luteinizing hormone

Answer: (C)

During days 1-13 of the menstrual cycle, follicle-stimulating hormone (FSH) is the hormone that is elevated. This phase is known as the follicular phase, which begins on the first day of menstruation. FSH is crucial for the growth and maturation of ovarian follicles. Elevated FSH levels stimulate the ovaries to produce estrogen, which prepares the endometrium for a potential pregnancy and supports the maturation of the eggs.

While estrogen does rise during this phase due to the development of the follicles, its elevation is secondary to the action of FSH. Progesterone, on the other hand, is primarily associated with the luteal phase of the cycle (days 15-28), following ovulation. Luteinizing hormone (LH) also peaks later in the cycle, especially leading up to ovulation. Therefore, it is the increase in FSH during days 1-13 that is significant for follicular development and the family of hormones involved in the early menstrual cycle.