Follicle-stimulating hormone, or FSH, is a hormone produced by the pituitary gland that plays a critical role in reproductive function. In women, FSH stimulates the growth and maturation of ovarian follicles, the fluid-filled sacs that contain developing eggs. In men, it supports sperm production. While FSH itself is measured through blood tests, its effects on the ovaries are directly monitored using transvaginal ultrasound during fertility treatments. Sonographers track the number and size of developing follicles in response to FSH injections to determine the optimal timing for egg retrieval or insemination. Understanding the relationship between FSH and follicular development helps sonographers interpret what they see during fertility ultrasound monitoring.
Sonography Term