8 Amenorrhoea may be defined as the failure of menstruation to occur at the expected time. It may be considered in two categories: 1. Primary amenorrhoea, when menstruation has never occurred. 2. Secondary amenorrhoea, when established menstruation ceases for 6 months or more. Failure to menstruate by the age of 16 is referred to as ‘primary amenorrhoea’. The likely cause of primary amenorrhoea depends on whether secondary sexual characteristics are present or not. If secondary sexual characteristics are absent, then the cause is most likely delayed puberty (see p. 45). If pubertal development is normal, then an anatomical cause should be suspected. The main ‘anatomical’ causes are: Failure to menstruate may also be physiological delay, in other words, the development is normal but there is an inherent delay in the onset of menstruation. There is often a family history of the same delay in the mother. A progestogen challenge test is useful to identify constitutional menstrual delay. A progestogen (e.g. norethisterone) is given orally for 5 days, and withdrawal should lead to a vaginal bleed. If such a bleed occurs, it is reasonable to offer reassurance that spontaneous menstruation is likely to occur. An abdominal ultrasound may be reassuring to confirm that the uterus and ovaries are normal. Low body weight and excessive exercise are also associated with primary amenorrhoea. The other causes listed in Table 8.1 are rare, although a few are outlined under the ‘secondary amenorrhoea’, discussion below (see also Chapters 5 and 6). Table 8.1 Causes of primary amenorrhoea Secondary amenorrhoea means the cessation of established menstruation. It is defined as no menstruation for 6 months in the absence of pregnancy. A full list of causes is given in Table 8.2, but the commonest are weight loss, polycystic ovary syndrome (PCOS) and hyperprolactinaemia. The more common conditions are discussed below. Table 8.2 Causes of secondary amenorrhoea
Amenorrhoea
Introduction
Primary amenorrhoea
congenital absence of the uterus; this is due to a failure of the Müllerian ducts to develop
imperforate hymen; the menstrual blood is retained within the vagina (a haematocolpos) causing cyclical lower abdominal pain each month at the time of menstruation (cryptomenorrhoea). Inspection of the vulva reveals a distended hymenal membrane through which dark blood may be seen and treatment by incision, usually under anaesthesia, is all that is required (Fig. 8.1).
System
Problem
Incidence
Chromosomal
XO – Turner syndrome
Rare
46,XY DSD
Rare
Ovotesticular DSD
Rare
Hypothalamic
Physiological delay
Common
Weight loss/anorexia/heavy exercise
Common
Isolated GnRH deficiency
Rare
Congenital CNS defects
Rare
Intracranial tumours
Rare
Pituitary
Partial/total hypopituitarism
Rare
Hyperprolactinaemia
Rare
Pituitary adenoma
Rare
Empty sella syndrome
Rare
Trauma/surgery
Rare
Ovarian
True agenesis
Rare
Premature ovarian failure
Rare
Radiation/chemotherapy/autoimmune
Rare
Polycystic ovaries
Common
Virilizing ovarian tumours
Rare
Other endocrine
Primary hypothyroidism
Rare
Adrenal hyperplasia
Rare
Adrenal tumour
Rare
Uterine/vaginal
Imperforate hymen
Not uncommon
Uterovaginal agenesis
Rare
Secondary amenorrhoea
System
Problem
Incidence
Physiological
Pregnancy
Common
Lactation
Common
Menopause
Common
Hypothalamic
Weight loss/anorexia
Common
Heavy exercise
Common
Stress
Common
Pituitary
Hyperprolactinaemia
Not uncommon
Partial/total hypopituitarism
Rare
Trauma/surgery
Rare
Ovarian
Polycystic ovary syndrome
Common
Premature ovarian failure
Uncommon
Surgery/radiotherapy/chemotherapy
Uncommon
Resistant ovary syndrome
Rare
Virilizing ovarian tumours
Rare
Other endocrine
Primary hypothyroidism
Rare
Adrenal hyperplasia
Rare
Adrenal tumour
Rare
Uterine/vaginal
Surgery – hysterectomy
Common
Endometrial ablation
Common
Progestogen intrauterine device
Common
Asherman syndrome
Rare
Causes
Physiological
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