The Role Of FSH In Reproductive Health
Follicle-stimulating hormone (FSH) is a hormone produced by the pituitary gland in the brain that plays a significant role in female reproduction. The hypothalamus controls FSH release and begins during puberty to promote sexual development and maturity. FSH works with luteinizing hormone (LH), also secreted by the pituitary gland, to regulate menstruation. FSH predominately functions to stimulate ovarian follicles to grow and prepare for ovulation. Follicles are fluid-filled sacs within the ovary that contain eggs. During the menstrual cycle, FSH stimulates a dominant follicle to release an egg during ovulation to be fertilized. FSH levels in the blood are critical to assessing fertility.
A healthy menstrual cycle
A normal menstrual cycle can be divided into two phases, the follicular and luteal phases, respectfully. The follicular phase marks the period when a follicle releases a mature egg, initiating ovulation. During this phase, FSH stimulates the follicles in the ovaries to release a mature egg. Another hormone, estrogen, is produced at this time, eliciting a decrease in FSH production by the pituitary gland in a negative feedback loop. LH is subsequently secreted as the cycle enters the second phase. This process, on average, lasts 28-35 days. Pregnancy rates increase if intercourse occurs during the 5 days leading up to ovulation and on the day of ovulation.
What if my FSH levels are high?
An FSH test is a valuable tool for assessing fertility potential. Consistently elevated FSH levels often indicate the reproductive system is malfunctioning. High FSH levels indicate that the body is working hard to ovulate. The pituitary gland will continue to produce FSH until estrogen is secreted by the ovary during ovulation, causing suppression. Other conditions can affect FSH release, including pituitary adenomas, which present with headaches, visual changes, and other hormonal deficiencies. A healthcare provider can evaluate elevated FSH levels and, based on the medical history, develop a plan to determine the best management course.
What if I have fewer eggs?
Females are born with a fixed number of 1-2 million eggs housed within the ovaries. Typically, at the onset of puberty, egg numbers have already begun to fall under 500,000 and continue to decline with age. A condition known as Diminished ovarian reserve syndrome (DOR) can affect fertility by decreasing the quantity and quality of eggs even further. Getting pregnant is more difficult as the eggs are less receptive to fertilization. Factors associated with DOR include smoking, ovarian surgery, genetics, and specific cancer therapies, including chemotherapy and pelvic radiation. Ovarian reserve testing can help, which consists of a combination of bloodwork to determine FSH and estradiol levels and ultrasound to measure approximate egg counts. Anti-mullerian (AMH) hormone, produced by the ovaries, is also measured and corresponds to the total number of eggs available. A healthcare provider specializing in assisted reproductive techniques (ART) can discuss treatment options to conceive.
Reproductive health and FSH
FSH can provide valuable information about infertility and difficulty conceiving. While a high FSH level can often be a sign of reduced egg quantity or quality, high levels do not always equal infertility. Understanding FSH levels and the critical role FSH plays in the menstrual cycle is essential in the path to pregnancy. An FSH test can assess fertility likelihood, and high levels may indicate a malfunctioning reproductive system or uncover a condition like DOR. Talking to a healthcare provider can help determine the best course when FSH levels are off the mark and pregnancy is the objective.
