Which hormone levels are characteristic of perimenopause and menopause?
Characteristic features are an early decline in AMH and inhibin B, followed by a rise in FSH and a late sharp fall in oestradiol. If you have symptoms, do not rely on a blood test alone, as hormone levels fluctuate considerably during the transition; discuss the pattern of your menstrual cycles and symptoms with your doctor.
The earliest hormonal signal of approaching menopause is the decline of inhibin B, a protein that reflects the number of active follicles in the ovary. This decline already occurs in women over 40 who are still menstruating normally, and after menopause inhibin B is no longer detectable at all. Anti-Mullerian hormone (AMH), which reflects the reserve of dormant follicles, declines even earlier than inhibin B. AMH is measurably lower approximately five years before the last menstrual period and has disappeared completely after menopause.
Because inhibin B drops away, it suppresses the pituitary gland less. This allows FSH to rise. FSH is therefore the first hormone that doctors typically measure, even though the rise is already visible early on. After menopause, FSH levels are strongly elevated. LH also rises, but less markedly. Oestradiol behaves surprisingly stable for a long time: because elevated FSH continues to stimulate the ovary, oestrogen levels remain largely maintained until late in perimenopause. Only in the three to four years surrounding the last menstrual period does oestradiol fall sharply. That decline is accompanied by hot flushes, sleep problems and loss of bone mass.
Testosterone follows a different pattern. It declines gradually throughout the entire reproductive lifespan (by approximately half between your twenties and forties), but menopause itself does not accelerate that decline. Testosterone can even rise slightly after menopause. Only when the ovaries are surgically removed does it fall noticeably further. DHEA and DHEAS, adrenal hormones that serve as precursors for sex hormones, decline with age, but this is a separate ageing process with no specific link to menopause.
After menopause, the adrenal glands partly take over the role of the ovaries. The adrenal glands produce androstenedione, which is converted to oestrogen in fatty tissue. Women with more body fat can therefore have slightly higher oestrogen levels after menopause than women with less body fat.
Practically important: during perimenopause, FSH and oestradiol are not reliable indicators for determining how far along you are in the transition. The values fluctuate enormously and overlap with values seen in younger women. A single blood test therefore says very little. The diagnosis of 'perimenopause' or 'menopause' is best established on the basis of your symptoms and the pattern of your menstrual cycles, and this should be discussed with your doctor.
This answer is based on multiple expert reviews, including broad overviews of the endocrinology of the menopausal transition. The picture of FSH, inhibin B and AMH as early markers is consistent across sources. Evidence on testosterone and DHEA is less clear-cut and the associations are weaker. No randomised studies are available that definitively establish cause and effect; most knowledge comes from long-term follow-up of women going through the transition.