Fertility testing usually involves blood tests (to measure for important hormones) and ultrasound.
Blood tests check for the following:
follicle stimulating hormone (FSH). This is the hormone that stimulates the fertile growth of the follicle containing the egg. If you are not having periods at all (amenorrhoea) it may be because this hormone is very low.
luteinising hormone (LH). This hormone stimulates the rapid growth of the follicle that contains the fertile egg just before ovulation. It may be normal or elevated in women with irregular or no periods; normal or low in women with no periods; and profoundly low in women who have lost so much weight as to place their health at risk.
prolactin (PRL). This hormone is normally elevated during pregnancy as it plays an important role in the preparation and establishment of breastfeeding. It may be raised in women who are not pregnant but whose periods have ceased or become very infrequent. This may be due to a small tumour in the pituitary gland or the use of particular medications.
thyrotrophin (TSH). The level of this hormone should be checked to see if the thyroid gland is underactive, which be linked with irregular periods.
androgens. Women with ovulation problems or who have polycystic ovarian syndrome (PCOS) may have elevated androgen levels.
An ultrasound gives good immediate information about the ovary. On ultrasound, the ovaries can be seen and measured. This helps the medical staff to know whether to proceed with fertility drugs or, if oestrogen levels are very low, with fertility injections.
An ultrasound may allow your doctor to see and evaluate simple cysts that might interfere with fertility drug treatments.
A diagnostic laparoscopy (keyhole investigation) may be recommended but only if you have period pain, significant discomfort during penetrative sex, a history of recurrent pelvic infection, or you have had an ultrasound that suggests a pelvic problem.
A sperm sample should also be tested, to discount a fertility issue in the man.