Primary Amenorrhoea : a review of five cases

Abstract

Regular menstruation is a feature of the reproductive physiology of only some primates. The cyclical nature of normal menstruation is a result of a complicated stimulatory and negative feed-back system of hormones secreted by an endocrinological axis composed of the hypothalamus, pituitary gland and ovaries in that order. The menarche is the time of onset of regular menstruation and is a result of a period of increasing hypo thalamic stimulation through releasing factors, upon the axis. The pituitary and ovaries in turn respond by secreting their own respective hormones each of which exerts a negative feed-back mechanism on its stimulatory hormone . It usually takes about 2 to 3 years for menstruation to become established regularly and a number of these cycles will be anovulatory. The menarche is to be dif- ferentiated from the puberty which is a longer process starting a number of years before the menarche and involving both striking physiological changes and important psychological aspects. We may consider the menarche to be only one part of the process of development that occurs during the puberty. Primary amenorrhoea is the failure of onset of menstruation. Although normal menstruation should be established by the age of sixteen there is no established age at which primary amenorrhoea should be investigated. In a patient with normal secondary sexual characteristics eighteen is often a reasonable age. Alternatively patients may be investigated four years after the development of the breasts. The breasts normally start to develop two years before the menarche. If amenorrhoea is associated with sexual infantilism, patients should be investigated at 15 to 16 years 0 even earlier. Primary amenorrhoea is not an uncommon problem facing gynaecologists. A good working classification of the aetiology of primary amenorrhoea is provided by Dewhurst (1981).