One FSH result usually cannot settle whether someone is moving through perimenopause. Hormone levels can rise and fall unpredictably during the transition, so the result needs the menstrual history and symptoms around it.[1]
What FSH measures
Follicle-stimulating hormone, or FSH, is made by the pituitary gland. It helps follicles in the ovaries develop and supports ovulation. As ovarian function changes, FSH may rise as the body signals the ovaries to respond.[2]
That makes FSH a useful part of some evaluations, but its meaning depends on why it was ordered. The same test can also be used in an infertility assessment or investigation of a pituitary or ovarian problem.[2]
Why age 43 changes the discussion
MedlinePlus says FSH testing usually is not needed to identify the usual menopause transition in people 45 or older. Testing may be appropriate when early menopause is suspected before 45 or when the reason for symptoms is unclear.[2]
At 43, the clinical question may include whether ovarian changes are occurring earlier than expected.
Read the report with its context
Useful context includes the pattern of recent periods, the date of the last period, hot flashes or night sweats, other symptoms and relevant medications. FSH is interpreted with age, medical history and sometimes other hormone tests.[1][2]
Laboratory reference ranges also vary. Comparing a result with an unrelated online cutoff can create confusion about what the testing laboratory actually measured.[3]
A clear interpretation explains how FSH fits the broader pattern and whether more information is needed.[1][2]
