Amenorrhoea is defined as the absence of menstrual periods for at least one year. The absence of periods also means the absence of ovulation or anovulation. Apart from during childhood, pregnancy, breastfeeding or menopause, the absence of the menstrual period may indicate a problem with the reproductive system.
One of the most common causes of amenorrhoea is hormonal disturbance.
High levels of Prolactin
This is the hormone responsible for milk production in the woman who is breast-feeding and the increased level causes amenorrhoea. Stress can increase prolactin levels to the point of causing amenorrhoea
Dysfunction of the Hypothalamus
When all other tests are normal it is accepted that the amenorrhoea is due to a dysfunction of the hormones produced in the hypothalamus gland. This hypothalamus is sited in the brain and controls the pituitary gland which in return is responsible for the production of FSH and LH - the hormones of ovulation and menstruation.
The interplay of female sex hormones can be disrupted by a wide range of events, including diseases of the reproductive organs, weight loss, emotional stress or overexercising.
Amenorrhoea is divided into two categories: Primary and secondary amenorrhoea
Menstruation hasn't begun by 14 years of age and the young woman shows no secondary sexual characteristics (such as developing breasts and pubic hair), or menstruation hasn't begun by 16 years of age, even though the young woman has secondary sexual characteristics.
Established menstruation has ceased for six months or for a length of time equivalent to a total of at least three of the previous cycle intervals.
The menstrual cycle
The hypothalamus and pituitary glands in the brain interact with each other to control the menstrual cycle. The pituitary gland produces chemicals that stimulate the ovaries to produce the two female sex hormones - oestrogen and progesterone. These hormones thicken the lining of the womb (uterus) to prepare for a possible pregnancy. When pregnancy doesn't occur, hormone levels drop and the lining of the womb falls away. This is called a period, or menstruation. The cycle then repeats. Disorders of the hypothalamus, pituitary gland or ovaries can disrupt menstruation and bring about amenorrhoea.
Disorders associated with Amenorrhoea
Polycystic ovary syndrome - the ovaries develop clusters of blister-like cysts. Associated symptoms include irregular periods and hirsutism (excessive hairiness).
Hyperandrogenaemia - the reproductive system is influenced by high levels of male sex hormones. This can be caused by ovarian or adrenal tumours, or certain congenital disorders.
Hyperprolactinaemia - an increase of the hormone prolactin caused by overactivity of, or a tumour on, the pituitary gland.
Early menopause - insufficient oestrogen levels cause ovulation to fail, which stops the menstrual cycle.
Abnormalities of the vagina - such as a sealed hymen, which prevents the menstrual blood from leaving the vagina. This is a rare condition and symptoms include abdominal distension and delayed start to periods and cyclical abdominal pain.
To determine the cause of Amenorrhea, your doctor apart from taking medical history and a physical examination, he/ she may prescribe the following:
- Pregnancy tests - either urine or blood tests.
- Hormone tests - to check the functioning of the hypothalamus, pituitary gland and ovaries.
- Other scans - including CT scans and ultrasounds of the reproductive system.
If the woman wishes to become pregnant she is managed as a problem of infertility. Where pregnancy is not the main consideration it is still necessary to help the woman achieve regular cycles with regular exposure to the hormones Oestrogen and Progesterone in order to avoid osteoporosis (thinning of the bones). Treatment for amenorrhoea depends on the cause. If extreme weight loss and excessive exercise are to blame, then treatment will focus on encouraging the woman to maintain a healthier body weight. Other treatment options may include managing the underlying disorder or using hormone replacement therapy (such as the combined oral contraceptive pill) to boost natural hormone levels.