Luteinising Hormone (LH)

Luteinizing hormone (LH) is a pituitary hormone that regulates reproductive function. In women it triggers ovulation, promotes corpus luteum formation and stimulates ovarian production of progesterone and estrogen. In men it acts on Leydig cells to stimulate testosterone production, supporting spermatogenesis. LH release is controlled by hypothalamic GnRH and feedback from sex steroids and inhibin.

Normal luteinizing hormone (LH) levels in females vary by menstrual phase. Typical reference ranges: follicular 1.9–12.5 mIU/mL; midcycle (surge/ovulation) 8.7–76.3 mIU/mL; luteal 0.5–16.9 mIU/mL. After menopause LH usually rises (about 15–62 mIU/mL). Values and units can differ between labs; consult your doctor for interpretation, especially for fertility or menstrual concerns.

When LH is high, repeat testing and see a clinician for endocrine evaluation. Your doctor will check FSH, sex steroids (estradiol or testosterone), prolactin and thyroid, and may order pelvic ultrasound or pituitary MRI. Management targets the cause—menopause, ovarian/testicular failure, PCOS or pituitary disorder—with treatments from fertility support or hormone therapy to addressing tumors. Review medications and lifestyle; follow specialist advice.

When luteinizing hormone (LH) is low, the gonads receive less stimulation. In women this causes irregular or absent periods, anovulation and infertility, plus low estrogen symptoms such as vaginal dryness and bone loss. In men it causes low testosterone, reduced libido, decreased muscle mass and sperm production, and possible infertility. Both sexes can experience delayed puberty, fatigue and higher osteoporosis risk.

High LH can result from primary gonadal failure—ovarian insufficiency or menopause in women, and testicular failure (e.g., Klinefelter syndrome) in men—causing loss of negative feedback. It’s commonly raised in PCOS (increased LH pulse frequency/ratio). Other causes include fertility medications (clomiphene, gonadotropins) and, rarely, LH-secreting pituitary tumours or genetic endocrine disorders.

Yes. Stress activates the HPA axis and raises cortisol and CRH, which can suppress hypothalamic GnRH secretion and alter LH pulsatility. Acute stress may transiently change LH peaks; chronic or severe stress can lower overall LH release, disrupt menstrual cycles, reduce ovulation and even cause amenorrhea. Managing stress can help restore normal reproductive hormone patterns.