Synonym/Acronym
LH, luteotropin, interstitial cell–stimulating hormone (ICSH).
Rationale
To assess gonadal function related to fertility issues and response to therapy.
Patient Preparation
There are no food, fluid, activity, or medication restrictions unless by medical direction.
Normal Findings
Method: Electrochemiluminescent Immunoassay.
| Concentration by Gender and by Phase (in Females) | Conventional and SI Units |
|---|
| Male | | | 1 mo–1 yr | Less than 0.5 international units/mL | | 2–10 yr | Less than 0.7 international units/mL | | 11 yr–Adult | Less than 9 international units/mL | | Adult | 1.2–9.6 international units/mL | | Female | | | 1 mo–6 yr | Less than 0.5 international units/mL | | 2–10 yr | Less than 0.7 international units/mL | | 11 yr–Adult | Less than 26 international units/mL | | Phase in Females | | | Follicular | 1.7–15 international units/mL | | Ovulatory | 14–96 international units/mL | | Luteal | 1–11 international units/mL | | Postmenopausal | 8–58 international units/mL |
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Study type: Blood collected in a gold-, red-, red/gray, or green-top [heparin] tube; related body system: Endocrine and Reproductive systems.
The secretion and inhibition of human reproductive hormones is maintained by a fine balance of feedback mechanisms involving the hypothalmus, pituitary gland, ovaries, and testes. Gonadotropin-releasing hormone (Gn-RH), a peptide neurohormone produced and released by the hypothalamus, signals the anterior pituitary gland to release luteinizing hormone and follicle-stimulating hormone. Gn-RH is secreted during the neonatal period, and gonadotropins are detectable in the blood at an early age. A negative feedback mechanism initiated by follicle-stimulating hormone and luteinizing hormone (LH) levels inhibits further secretion by suppressing the release of Gn-RH until puberty.
During the prepubital period and following into adulthood, nocturnal pulses of Gn-RH induce nocturnal, pulsatile secretions of LH. LH affects gonadal function in both men and women. In women, a surge of LH normally occurs at the midpoint of the menstrual cycle (ovulatory phase) due to initiation of a positive feedback loop involving estrogen and which results in ovulation. As the corpus luteum develops, progesterone levels rise, signaling the pituitary to stop secreting LH. In males, LH stimulates the interstitial cells of Leydig, located in the testes, to produce testosterone. For this reason, in reference to males, LH is sometimes called interstitial cell–stimulating hormone. Serial specimens may be required to accurately demonstrate blood levels.
Factors That May Alter the Results of the Study
- Drugs and other substances that may increase LH levels include clomiphene, gonadotropin-releasing hormone, goserelin, ketoconazole, leuprolide, mestranol, nafarelin, naloxone, nilutamide, spironolactone, and tamoxifen.
- Drugs and other substances that may decrease LH levels include anabolic steroids, anticonvulsants, conjugated estrogens, cyproterone, danazol, digoxin, D-Trp-6-LHRH, estradiol valerate, estrogen/progestin therapy, finasteride, ganirelix, goserelin, ketoconazole, leuprolide, desogestrel/ethinylestradiol (Marvelon), medroxyprogesterone, megestrol, metformin, octreotide, oral contraceptives, phenothiazine, pimozide, pravastatin, progesterone, and tamoxifen.
Other Considerations
- In menstruating women, values vary in relation to the phase of the menstrual cycle.
- LH secretion follows a circadian rhythm, with higher levels occurring during sleep.
Increased In
Conditions of decreased gonadal function cause a feedback response that stimulates LH secretion.
Decreased In
- Anorexia nervosa(pathophysiology is unclear)
- Kallmann syndrome(pathophysiology is unclear)
- Malnutrition(pathophysiology is unclear)
- Pituitary or hypothalamic dysfunction (these organs control production of LH; failure of the pituitary to produce LH or of the hypothalamus to produce gonadotropin-releasing hormone results in decreased LH levels)
- Severe stress (pathophysiology is unclear)
Before the Study: Planning and Implementation
Teaching the Patient What to Expect
- Discuss how this test can assist in assessing hormone and fertility disorders.
- Explain that a blood sample is needed for the test.
- Review the procedure with the patient.
- If the test is being performed to detect ovulation, inform the patient that it may be necessary to obtain a series of samples over a period of several days to detect peak LH levels.
After the Study: Implementation & Evaluation Potential Nursing Actions
Treatment Considerations
- Record the date of the last menstrual period and determine the possibility of pregnancy in women who are perimenopausal.
- Fertility issues can be an emotional land mine for many people.
- Failure to conceive can cause great anxiety and engender feelings of hopelessness and depression and a sense of powerlessness that affect the patient’s sense of self.
- Discuss how the purpose of repeating laboratory studies is to monitor and trend hormone levels.
- Encourage verbalization of feelings and discuss therapeutic options offered by the health-care provider (HCP)
- Facilitate referral to fertility counseling as appropriate to diagnosis.
Clinical Judgement
- Consider ways to manage emotional responses to failure to conceive.
Follow-Up and Desired Outcomes
- States the proper use of home ovulation test kits approved by the U.S. Food and Drug Administration.
- Understands the alternative methods to achieve pregnancy, as described by HCP.