Subfertility

Published on 02/03/2015 by admin

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Last modified 22/04/2025

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Subfertility

Subfertility is defined as the failure of a couple to conceive after one year of regular, unprotected intercourse. A full clinical history obtained prior to physical examinations should seek information about previous pregnancies, contraceptive practice, serious illnesses, past chemotherapy or radiotherapy, congenital abnormalities, smoking habits, drug usage, sexually transmitted disease and the frequency of intercourse. Physical examination should look for indications of hypothalamic–pituitary or thyroid disorders, Cushing’s syndrome, galactorrhoea and hirsutism. In the male, semen analysis should detail volume, sperm density, motility and the presence of abnormal spermatozoa.

In the female, endocrine abnormalities are found in one-third of patients. Hormone dysfunction is a very rare cause of male subfertility. In some couples no cause can be identified.

Endocrine investigations in the subfertile woman

The investigation of the infertile female depends on the phase of the menstrual cycle. If there is a regular menstrual cycle, serum progesterone should be measured in the middle of the luteal phase (day 21). If progesterone is high (>30 nmol/L), the patient has ovulated and there is no need for further endocrine investigations. Other causes of subfertility should be sought. If progesterone is low (<10 nmol/L), ovulation has not occurred.

In women who present with irregular or absent menstruation (oligomenorrhoea or amenorrhoea) or who are not ovulating, hormone measurements may be diagnostic. A protocol for investigation is shown in Figure 51.1. Measurement of oestradiol and gonadotrophin concentrations may detect primary ovarian failure or polycystic ovarian disease. Measurement of prolactin, and androgens, may also assist.

Fig 51.1 Diagnostic approach to subfertility in the woman.

Endocrine causes of subfertility in women include:

Excessive androgen secretion by the ovaries in response to insulin resistance. This is commonly a feature of central obesity.

Primary ovarian failure. This is indicated by elevated gonadotrophins and low oestradiol concentration (a postmenopausal pattern). Hormone replacement therapy assists libido and prevents osteoporosis, but does not restore fertility.

Hyperprolactinaemia (pp. 84–85).

Polycystic ovarian disease. This is indicated by an elevated LH and normal FSH. Oestradiol measurements are often unhelpful. Hirsutism, a feature of this condition, is associated with raised testosterone and subnormal sex hormone binding protein concentrations.

Cushing’s syndrome (pp. 98–99).

Hypogonadotrophic hypogonadism. Rarely, subnormal gonadotrophin and oestradiol concentrations suggest the presence of a hypothalamic–pituitary lesion such as interference from a pituitary tumour.

Endocrine investigations in the subfertile man

In the eugonadal male with normal sperm analysis, no endocrine investigations are required. In the hypogonadal male, testosterone and the gonadotrophins should be measured first (Fig 51.2). Causes of subfertility in the male include:

Fig 51.2 Diagnostic approach to subfertility in the man.

Primary testicular failure. Where both the interstitial cells and tubules are damaged, FSH and LH will be elevated and testosterone reduced. Where tubular function only is impaired, FSH is selectively increased and androgen levels may be normal.

Hypothalamic–pituitary disease. Decreased testosterone with low or normal gonadotrophins suggests hypogonadotrophic hypogonadism.

Hyperprolactinaemia. This is a rare cause of subfertility in the male (pp. 84–85).

Subfertility

Endocrine problems are a common cause of subfertility in the female but are rare in the male.

An elevated serum progesterone in a specimen at day 21 of the menstrual cycle indicates that ovulation has occurred.

In both men and women a serum FSH concentration greater than 25 U/L indicates primary gonadal failure.

Hyperprolactinaemia is a common cause of female subfertility.

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