Hormone Biomarkers: Luteinizing Hormone in Women

Optimal Takeaways

Luteinizing hormone (LH) is a pituitary hormone that affects the ovaries and the production and regulation of estrogen, ovulation, and fertility in women. LH works closely with follicle-stimulating hormone (FSH) and both are evaluated when investigating infertility. A surge of LH is seen in the blood 24 hours prior to ovulation, indicating a period of maximum fertility. Low levels are seen with failure of the pituitary or hypothalamus, stress, malnutrition, certain medications, and pesticide exposure. Higher levels are seen with menopause, polycystic ovaries, pituitary adenoma, and certain medications. Higher levels in the blood may be associated with lower levels in the brain which can contribute to cognitive impairment.

Standard Ranges (Immunoassay)

• Follicular Phase: 1.9-12.5 mIU/mL
• Mid-Cycle Peak 8.7-76.3 mIU/mL
• Luteal Phase: 0.5-16.9 mIU/mL
• Postmenopausal: 10.0-54.7 mIU/mL

Low levels of luteinizing hormone may be caused by stress, malnutrition, anorexia nervosa, or failure of the pituitary or hypothalamus glands. Decreased levels may be caused by medications such as estrogen, oral contraceptives, progesterone, testosterone, phenothiazines, digoxin (Pagana 2021), as well as exposure to pesticides (Lambertino 2020). A low LH may also be associated with caloric deficit, amenorrhea (Orlowski 2021), and poorer outcomes for assisted reproductive technology (Nedresky 2021).

High levels of luteinizing hormone may be seen in menopause, polycystic ovaries, Turner Syndrome, precocious puberty, and pituitary adenoma. Increased LH may be caused by anticonvulsants, clomiphene, naloxone, and spironolactone. Levels may be falsely elevated with hypothyroidism and hCG-producing tumors (Pagana 2021). High levels in the blood may be associated with low levels in the brain which can interfere with memory and cognition (Blair 2015).

Overview

Luteinizing hormone (LH) is a glycoprotein produced in the anterior pituitary with effects on the ovary and testes. In women, serum levels spike approximately 24 hours prior to ovulation, a period of time when a women’s fertility peaks (Pagana 2021).

LH stimulates production of steroid hormones in the ovaries, with estrogen then feeding back to inhibit further LH production. LH also assists in ovulation, egg implantation, and regulation of the menstrual cycle. LH supplementation for assisted reproduction technology may have some benefits but may have drawbacks as well (Nedresky 2021).

The normal cyclic surge that occurs in serum LH can vary widely among menstruating women. However, researchers note 2 patterns that may negatively affect the ovulation process. These include multiple peaks in serum LH prior to ovulation which may indicate follicular insufficiency, and a prolonged LH surge of greater than 3 days following ovulation which may indicate luteal insufficiency (Direito 2013).

Luteinizing hormone appears to have direct effects on the central nervous system and cognition, with elevated serum levels being associated with decreased brain LH which may contribute to cognitive decline and learning and memory deficits. Interestingly, a reduction in the elevated surge of serum LH that occurs during menopause or post-ovariectomy may help increase and normalize brain levels of LH, which can potentially improve cognition (Blair 2015). Animal research suggests that supporting an increase in estrogen and a decrease in serum LH may help improve spatial memory, an action that may be dependent on brain-derived neurotrophic factor (Bohm-Levine (2020).

A study of 21 women newly diagnosed with PCOS confirmed that elevated LH levels were associated with a decrease in cognitive function including visuospatial memory, episodic memory, and face processing in this group (Lai 2020).

References

Blair, Jeffrey A et al. “Luteinizing hormone: Evidence for direct action in the CNS.” Hormones and behavior vol. 76 (2015): 57-62. doi:10.1016/j.yhbeh.2015.06.020

Bohm-Levine, Nathaniel et al. “Reducing luteinizing hormone levels after ovariectomy improves spatial memory: Possible role of brain-derived neurotrophic factor.” Hormones and behavior vol. 118 (2020): 104590. doi:10.1016/j.yhbeh.2019.104590

Direito, Ana et al. “Relationships between the luteinizing hormone surge and other characteristics of the menstrual cycle in normally ovulating women.” Fertility and sterility vol. 99,1 (2013): 279-285.e3. doi:10.1016/j.fertnstert.2012.08.047

Lai, Wanlin et al. “Plasma luteinizing hormone level affects the brain activity of patients with polycystic ovary syndrome.” Psychoneuroendocrinology vol. 112 (2020): 104535. doi:10.1016/j.psyneuen.2019.104535

Nedresky, Daniel. and Gurdeep Singh. “Physiology, Luteinizing Hormone.” StatPearls, StatPearls Publishing, 28 September 2021.

Orlowski, Michelle. and Manbeer S. Sarao. “Physiology, Follicle Stimulating Hormone.” StatPearls, StatPearls Publishing, 9 May 2021.

Pagana, Kathleen Deska, et al. Mosby's Diagnostic and Laboratory Test Reference. 15th ed., Mosby, 2021.