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Ovarian disorders 

Ovarian disorders

Chapter:
Ovarian disorders
Author(s):

Stephen Franks

and Lisa J. Webber

DOI:
10.1093/med/9780199204854.003.130801

November 30, 2011: This chapter has been re-evaluated and remains up-to-date. No changes have been necessary.

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date: 25 March 2017

The ovary produces (1) gametes—germ cells in the ovary have undergone the first meiotic division to become oocytes in primordial follicles by the time of birth, with about 400 of these ovulating during reproductive life; and (2) hormones—oestradiol, progesterone, androgens, and two nonsteroidal glycopeptides, inhibin A and B.

Ovulation and hormonal secretion is regulated by the pituitary gonadotropins, follicle-stimulating hormone (FSH) and lutenizing hormone (LH), production of which is controlled by pulsatile release of the decapeptide gonadotropin-releasing hormone (GnRH) from the hypothalamus. LH and FSH act on maturing ovarian follicles: LH inducing androgen secretion from the thecal layer, and FSH stimulating the inner granulosa cell layer to aromatize androgens to generate oestrogens. After ovulation, the corpus luteum produces oestradiol as well as progesterone: these two hormones, together with inhibins, exert feedback inhibition on gonadotropin release.

In the normal menstrual cycle, differential sensitivity to FSH leads to the further growth of a dominant follicle which becomes responsive to LH, with enhanced steroidogenesis and greatly increased oestradiol concentrations. These prevailing conditions trigger a surge in the production of LH, a unique positive feedback phenomenon that induces resumption of meiosis in the oocyte and ovulation by rupture of the follicle, which is then induced to secrete abundant progesterone. Progesterone suppresses gonadotrophin release and—if trophoblastic gonadotrophin secretion fails to occur (in the absence of fertilization and pregnancy)—the corpus luteum breaks down, inducing the onset of a new cycle.

Amenorrhoea

Involuntary infertility affects about one in six couples, with ovulatory disorders accounting for 25 to 30%.

Aetiology—the condition may be (1) primary—menarche delayed beyond 16 years, no previous periods; may be caused by developmental disorders (see Chapter 13.9.1); or (2) secondary—at least one previous spontaneous period; may be caused by primary ovarian failure, hypothalamic/pituitary dysfunction and polycystic ovary syndrome (PCOS). Oligomenorrhoea (more than 6 weeks between periods) is most commonly caused by polycystic ovary syndrome.

Premature (primary) ovarian failure—defined as ovarian failure at <40 years; cause unknown in most cases but may be associated with organ-specific autoimmune diseases and chromosomal abnormalities (e.g. Turner syndrome, 45X); high FSH, low oestrogen; often treated with hormone replacement therapy (HRT).

Hypothalamic/pituitary disorder—characterized by low FSH, low oestrogen; most commonly related to (a) weight loss—often associated with an underlying eating disorder that may benefit from specialist psychological/psychiatric treatment; GnRH or FSH is unwise until normal BMI has been achieved; or (b) hyperprolactinaemia—see Chapter 13.2.

PCOS—typically presents with amenorrhoea in association with clinical signs of hyperandrogenism (hirsutism, persistent acne, male pattern alopecia); wider definition requires two of (1) oligo- and/or anovulation, (2) clinical and/or biochemical signs (raised serum testosterone) of hyperandrogenism, and (3) polycystic ovaries.

PCOS is associated with a metabolic disorder including insulin resistance/hyperinsulinaemia/impaired glucose tolerance and dyslipidaemia. Management is mainly targeted at relief of symptoms with diet, antiandrogens (e.g. cyproterone acetate, spironolactone). Anovulatory women who wish to conceive usually respond to ovulation induction therapy (e.g. clomiphene).

Hirsutism

Mild to moderate long-standing hirsutism in women with regular menses is very likely to be associated with PCOS, which can be confirmed by finding normal/slightly elevated serum testosterone concentration and pelvic ultrasonography to determine ovarian morphology.

Patients with a short history of hirsutism (particularly if severe), symptoms suggesting other endocrine disorders (e.g. Cushing’s syndrome), and/or serum testosterone above 5 nmol/litre (normal range 0.5–3.0) require further investigation including ovarian and/or adrenal imaging (for androgen-secreting tumour) and biochemical tests for Cushing’s syndrome and congenital adrenal hyperplasia (see Chapter 13.7.2).

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