At a Glance
Amenorrhea is the absence of menstrual blood flow. Primary amenorrhea should be considered in any patient with secondary sex characteristics who has not experienced periodic menstruation by 15 years of age or 5 years after breast development. Patients who have not developed secondary sex characteristics, especially the absence of breast development, and have not established periodic menstruation by 13 years of age should also be worked up for primary amenorrhea.
Premature ovarian failure (POF) is defined as primary hypogonadism in premenopausal women. Its clinical presentations are heterogeneous. However, most patients present with amenorrhea and hypergonadotropic hypogonadism. The absence of or limited ovarian function prior to and during puberty in patients with POF results in low or no estrogen secretion and minimal to no development of secondary sex characteristics. Adrenal androgens may induce production of pubic hair, but patients will have minimal breast development. POF has numerous etiologies, including genetic mutations, chromosomal anomalies, Turner syndrome, autoimmune disease, environmental insults, and idiopathic, but all must occur prior to onset of menstruation to cause primary amenorrhea (see chapter on Turner Syndrome).
What Tests Should I Request to Confirm My Clinical Dx? In addition, what follow-up tests might be useful?
The work-up for primary amenorrhea begins with a careful history and physical exam to look for anatomical defects, development of secondary sexual characteristics, and/or a personal or family history of delayed puberty, mental retardation, short stature, cancer, autoimmune disease, infertility, and/or amenorrhea. Physical exam of patients with suspected ovarian failure should look for characteristic features of Turner syndrome (see chapter on Turner Syndrome) (i.e., short stature, a webbed neck, and edema of the hands and feet) and/or unambiguous female genitalia with minimal development of secondary sex characteristics (ie, pubic hair, but no breast development).
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About 5% of women with POF conceive naturally, because they retain periodic ovarian function. Thus, the laboratory work-up for primary amenorrhea due to POF should begin with measurement of human chorionic gonadotropin (hCG) to rule out pregnancy. If not pregnant, patients should undergo imaging studies looking for a uterus and gonads. Patients with POF may have streak or dysfunctional gonads, but a normal prepubescent uterus.
In patients with a detectable uterus, hypothyroidism and prolactinemia should be ruled out. A high thyroid stimulating hormone (TSH) result suggests the amenorrhea is due to primary hypothyroidism and should be followed with fT4 analysis. A reduced fT4 confirms hypothyroidism. An elevated prolactin result should prompt a physician to perform an MRI in search of a pituitary adenoma. Prolactin inhibits gonadotropin function, thus, causing amenorrhea in nursing mothers and patients with prolactinomas.
Patients with normal TSH and prolactin should be evaluated for POF by measuring luteinizing hormone (LH) and follicle stimulating hormone (FSH) to assess gonadotropic function. Although suggested by the lack of secondary sex characteristics, estrogen measurements may also be helpful. Low estrogen concentrations are expected in patients with POF.
Because of day-to-day variability in estrogen concentrations, the progestin challenge test may be helpful to establish estrogen reserves and/or etiology of primary amenorrhea in patients with suspected POF, an intact uterus and some secondary sex characteristics. Theoretically, if progesterone is given to an estrogen primed uterus, withdrawal bleeding (menses) will occur. Progesterone is given orally for up to 1 week. Bleeding should occur within 1 week of progesterone withdrawal if the woman’s ovaries have produced enough estrogen (>40 pg/mL serum) to prime her uterus. A woman with POF should not respond appropriately to progesterone withdrawal; however, about 20% of patients with POF will bleed 1 week after stopping progesterone.
High concentrations of FSH and/or LH combined with low estrogen concentrations or a failed progesterone challenge test are suggestive of ovarian failure. POF is confirmed if FSH is elevated and estrogen is low on two separate specimens; however, the etiology of POF still needs determined.(Table 1)
Table 1.
| FSH | Estradiol |
|---|---|
| >30 mIU/mL | <50 pg/mL |
Are There Any Factors That Might Affect the Lab Results? In particular, does your patient take any medications – OTC drugs or Herbals – that might affect the lab results?
False-negative results can occur with urine pregnancy tests and may result in a misdiagnosis. False-negative results can occur if urine is too dilute. To ensure an appropriate urine specimen, perform urine pregnancy testing on first morning voids and check the protein concentration by measuring the urine specific gravity and/or urine creatinine. False-negative results may also be caused by the variant effect. This phenomenon occurs when high concentrations of hCG isoforms in urine (hCG beta core fragment) are not recognized by both antibodies in the assay. Instead, they interfere with one antibody and cause a false-negative result. One can test for the variant effect by diluting the urine sample and repeating the testing.
Prolactin is mildly elevated by stress, herpes simplex virus (HSV) infections in the chest wall, and numerous drugs, including dopamine agonists, proton pump inhibitors, antipsychotics (risperidone, phenothiazines, haloperidol), antihypertensives (methyldopa, reserpine, verapamil), estrogens, and illicit drugs (eg, amphetamines, cannabinoids, opiates, etc). Any of these may lead to dysregulation of gonadotropins, amenorrhea, and infertility.
LH and FSH are episodically released from the pituitary, and concentrations may vary, depending on when they are measured. First morning specimens are recommended. LH and FSH concentrations change throughout the menstrual cycle, even in amenorrheic patients. Measure LH and FSH early in the follicular phase of the cycle, if possible.
Concentrations of LH and FSH change dramatically during puberty. Results should be evaluated in the context of age and Tanner stage specific reference intervals. Drugs, such as anticonvulsants, clomiphene, and naloxone, may falsely elevated LH, whereas smoking, cimetidine, clomiphene, digitalis, and levodopa elevate FSH. Artificially low LH and FSH results may occur in patients taking oral contraceptives and hormone treatments. Phenothiazines reduce FSH concentrations, whereas digoxin decreases LH.
Estrogen can be measured by immunoassay or LC/MS/MS. Because immunoassays are imprecise at low concentrations, it is recommended that estrogen be measured by LC/MS/MS in men, children, and early Tanner stages. Estrogen concentrations vary throughout the menstrual cycle, even in amenorrheic women, and should be measured in the early follicular phase of the cycle if possible. Chronic illnesses, such as anemia, hypertension, and liver and kidney diseases affect estrogen concentrations.
Several Estrogen containing drugs, such as birth control pills and hormone replacements, may interfere with the assays causing falsely elevated results. Glucocorticoids, antibiotics (ampicillin and tetracycline), and phenothiazines may also cause false elevations in estrogen measurements. Clomiphene and oral contraceptives may reduce estrogen concentrations.
Patients with excess androgen concentrations may not respond to the progestin challenge test. Further, patients with obesity and/or severe stress may respond to the progestin challenge testing with withdrawal bleeding despite gonadal failure (false-negative results).
As is the case with many immunoassays, heterophilic antibodies can cause false-positive results. Therefore, caution should be taken when elevated hCG, TSH, prolactin, estradiol, LH, and/or FSH results do not match the clinical picture.
What Lab Results Are Absolutely Confirmatory?
False-negative results can occur with urine pregnancy tests and may result in a misdiagnosis. False-negative results can occur if urine is too dilute. To ensure an appropriate urine specimen, perform urine pregnancy testing on first morning voids and check the protein concentration by measuring the urine specific gravity and/or urine creatinine. False-negative results may also be caused by the variant effect. This phenomenon occurs when high concentrations of hCG isoforms in urine (hCG beta core fragment) are not recognized by both antibodies in the assay. Instead, they interfere with one antibody and cause a false-negative result. One can test for the variant effect by diluting the urine sample and repeating the testing.
Prolactin is mildly elevated by stress, herpes simplex virus (HSV) infections in the chest wall, and numerous drugs, including dopamine agonists, proton pump inhibitors, antipsychotics (risperidone, phenothiazines, haloperidol), antihypertensives (methyldopa, reserpine, verapamil), estrogens, and illicit drugs (eg, amphetamines, cannabinoids, opiates, etc.). Any of these may lead to dysregulation of gonadotropins, amenorrhea, and infertility.
LH and FSH are episodically released from the pituitary, and concentrations may vary, depending on when they are measured. First morning specimens are recommended. LH and FSH concentrations change throughout the menstrual cycle, even in amenorrheic patients. Measure LH and FSH early in the follicular phase of the cycle, if possible.
Concentrations of LH and FSH change dramatically during puberty. Results should be evaluated in the context of age and Tanner stage specific reference intervals. Drugs, such as anticonvulsants, clomiphene, and naloxone, may falsely elevated LH, whereas smoking, cimetidine, clomiphene, digitalis, and levodopa elevate FSH. Artificially low LH and FSH results may occur in patients taking oral contraceptives and hormone treatments. Phenothiazines reduce FSH concentrations, whereas digoxin decreases LH.
Estrogen can be measured by immunoassay or LC/MS/MS. Because immunoassays are imprecise at low concentrations, it is recommended that estrogen be measured by LC/MS/MS in men, children, and early Tanner stages. Estrogen concentrations vary throughout the menstrual cycle, even in amenorrheic women, and should be measured in the early follicular phase of the cycle if possible. Chronic illnesses, such as anemia, hypertension, and liver and kidney diseases affect estrogen concentrations.
Several Estrogen containing drugs, such as birth control pills and hormone replacements, may interfere with the assays causing falsely elevated results. Glucocorticoids, antibiotics (ampicillin and tetracycline), and phenothiazines may also cause false elevations in estrogen measurements. Clomiphene and oral contraceptives may reduce estrogen concentrations.
Patients with excess androgen concentrations may not respond to the progestin challenge test. Further, patients with obesity and/or severe stress may respond to the progestin challenge testing with withdrawal bleeding despite gonadal failure (false-negative results).
As is the case with many immunoassays, heterophilic antibodies can cause false-positive results. Therefore, caution should be taken when elevated hCG, TSH, prolactin, estradiol, LH, and/or FSH results do not match the clinical picture.
What Tests Should I Request to Confirm My Clinical Dx? In addition, what follow-up tests might be useful?
Although detection of streak gonads on ovarian biopsy confirms one cause for POF (gonadal dysgenesis), its utility in patients with primary amenorrhea is questionable. Pregnancies have occurred in karyotypic females (46,XX) with premature ovarian failure and no gonadal follicles noted on biopsy. The only practical use for ovarian biopsy is in patients with Y chromosome material. The presence of Y chromosome material increases a patient’s risk for gonadoblastoma, thus, gonadectomy is recommended for all patients with POF and hidden Y mosaicism. The presence of Y chromosome mosaicism should be confirmed in any patient with virilization and/or Y chromosome material by identifying the SRY region via FISH or DNA analysis.
Are There Any Factors That Might Affect the Lab Results? In particular, does your patient take any medications – OTC drugs or Herbals – that might affect the lab results?
Progesterone is elevated in pregnant women and those taking oral contraceptives.
Chemotherapy and/or radiation may affect the yield of metaphase chromosomes, reducing the ability to perform karyotyping analyses.
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