Which one of the following hormones is at its peak during ovulation?

The correct answer is Option (3) → Luteinising hormone

Note 1: The given answer is as per the official NTA Answer Key. However, the question can have more than one correct answer, i.e. both Option (3) and Option (4), because NCERT says that both LH and FSH attain a peak in the middle of the menstrual cycle, as explained below.

In the menstrual cycle, FSH from the pituitary makes the follicles grow, and the growing follicles secrete estrogens. In the middle of the cycle (about the 14th day), a rapid rise of LH to its maximum, called the LH surge, makes the Graafian follicle rupture and release the ovum. This release is ovulation.

(1) Progesterone — Incorrect. It is secreted by the corpus luteum, which forms from the ruptured follicle after ovulation. It peaks in the luteal phase, not at ovulation.

(2) Estrogen — Incorrect. It rises through the follicular phase and is at its highest just before the LH surge, which it helps to start. It is not the hormone that NCERT names as peaking at ovulation.

(3) Luteinising hormone — Correct. Its surge is the sharpest peak of the cycle, and it is the hormone that directly causes ovulation. This is the answer given by NTA.

(4) Follicle stimulating hormone — Also correct as per NCERT. NCERT says that both LH and FSH attain a peak in the middle of the cycle. The FSH peak is smaller and does not itself rupture the follicle.

Note 2: A similar question was also asked in CUET (UG) 2025 on 13-05-2025 (Slot 2).

NCERT Extract:
Menstrual Cycle – “… The secretion of gonadotropins (LH and FSH) increases gradually during the follicular phase, and stimulates follicular development as well as secretion of estrogens by the growing follicles. Both LH and FSH attain a peak level in the middle of cycle (about 14th day). Rapid secretion of LH leading to its maximum level during the mid-cycle called LH surge induces rupture of Graafian follicle and thereby the release of ovum (ovulation).”
Gametogenesis – “… The increased levels of GnRH then acts at the anterior pituitary gland and stimulates secretion of two gonadotropins - luteinising hormone (LH) and follicle stimulating hormone (FSH).”