The diagnosis of the underlying cause of infertility involves several steps. Upon having experienced failure to conceive after months of attempts, visits to the doctor, and referrals to specialists and other practitioners, more in-depth diagnostic exams may follow. These may range from diagnostic imaging, such as x-ray, ultrasound and CT scan, to blood tests for blood count as well as chemical and hormone levels.
Hormones that are usually checked in female patients faced with infertility include FSH, LH, and estradiol. The screening process involves taking a blood sample, 24-hour urine sample; or in the case of estradiol, a fresh saliva sample and comparing the levels in the patient against a range of normal values. Findings outside the normal values, whether too high or too low can provide valuable evidence for determining the underlying cause of infertility.
In terms of in-vitro fertilization, FSH, or follicle-stimulating hormone, regulates the reproductive processes of the human body. In women, FSH stimulates the growth and recruitment of immature ovarian follicles in the ovary. LH, or luteinizing hormone, functions in concert with FSH, signaling ovulation and is involved with the development of the corpus luteum. Estradiol, a sex hormone, is the predominant form of estrogen in adult women.
FSH blood tests are often done to investigate a woman’s irregular menstrual cycle, or if her periods have stopped altogether. LH blood tests are not only performed to evaluate ovulation, but are also sometimes done to evaluate hypothalamic function. The tests for FSH and LH are performed to workup a patient for infertility, as well as disorders of the pituitary gland and reproductive system.
The following table summarizes normal levels of FSH, LH, and estradiol, and what abnormal measurements may indicate:
| Hormone | Collection Method | Abnormally Low | Abnormally High |
| FSH | Blood, 24-hour urine | Oral contraceptive use, hormone therapies | Primary Ovarian Failure |
| LH | Blood, 24-hour urine | Excessive exercise, eating disorder, hypogonadism, hyperprolactinemia, hypopituitarism | Primary Ovarian Failure, premature menopause, Turner syndrome, PCOS, Congenital adrenal hyperplasia |
| Estradiol | Blood, 24-hour urine, fresh saliva | Turner syndrome, hypopituitarism, hypogonadism, post-menopause, PCOS | Ovarian tumor, hyperthyroidism, liver cirrhosis |
The utility of the FSH and LH tests lies in their ability to evaluate primary ovarian failure. In this disorder, levels of FSH and LH are increased. Among the causes of primary ovarian failure include developmental defects such as ovarian agenesis, chromosomal abnormality, and 17-alpha hydroxylase deficiency. Ovarian failure can also be due to autoimmune disease, or can be chronic in nature, owing to polycystic ovarian syndrome, thyroid disease, and ovarian tumor.
When undergoing workup for infertility using FSH, LH and estradiol tests, it is important to note that certain drugs can skew the results. Cimetidine, clomiphene, digitalis and levodopa increase FSH and LH, whereas oral contraceptives and hormone therapies render decreased levels. Glucocorticosteroids, ampicillin, as well as tetracyclines increase serum estradiol levels. Like FSH and LH, these levels are seen to be decreased in patients using oral contraceptives.