Amenorrhoea or amenorrhea is the absence of a menstrual period in a woman of reproductive age. Physiologic states of amenorrhoea are seen during pregnancy and lactation (breastfeeding). Outside of the reproductive years there is absence of menses during childhood and after menopause.
The term is derived from Greek: a = negative, men = month, rhoia = flow. Derived adjectives are amenorrhoeal and amenorrheic. The opposite is the normal menstrual period.
There are two types of amenorrhoea, primary and secondary amenorrhoea. Primary amenorrhoea is the absence of menstruation in a woman by the age of 16. Also, as pubertal changes precede the first period, menarche, women who have no sign of thelarche or pubarche and thus are without evidence of iniation of puberty by the age of 14 have primary amenorrhoea. (Reference: Speroff L et al, Clinical Gynecologic Endocrinology and Infertility, 1999)
Secondary amenorrhoea is where an established menstruation has ceased for about six months or the time of three menstrual cycles.
Amenorrhoea is a symptom with many potential causes. Primary amenorrhoea may be caused by developmental problems such as the congenital absence of the uterus, or failure of the ovary to receive or maintain egg cells. Also, delay in pubertal development will lead to primary amenorrhoea. Secondary amenorrhoea is often caused by hormonal disturbances from the hypothalamus and the pituitary gland or from premature menopause, or intrauterine scar formation.
Hypogonadotropic amenorrhoea refers to conditions where there are very low levels of serum FSH and LH. Generally, inadequate levels of these hormones lead to inadequately stimulated ovaries who then fail to produce enough estrogen to stimulate the endometrium(uterine lining), hence amenorrhoea. This is typical for conditions of pubertal delay, hypothalamic or pituitary dysfunction. In general women with hypogonadotropic amenorrhoea are potentially fertile.
Hypergonadotropic amenorrhoea refers to conditions with high levels of FSH (and LH). FSH levels are typically in the menopausal range. This implies that the ovary or gonad does not respond to pituitary stimulation. Gonadal dysgenesis or premature menopause are possible causes. Chromosome testing is usually indicated in younger individuals with hypergonadotropic amenorrhoea.
In normogonadotropic amenorrhea, FSH levels are in the nomal range. This would suggest that the hypothalamic-pituitary-ovarian axis is functional. Amenorrhea may be due to outflow obstruction, or abnormal ovarian regulation or excess androgens as seen in polycystic ovary syndrome.
Primary amenorrhoea
1. Gonadal dysgenesis, including Turner Syndrome.
2. Mullerian agenesis (Muller-Rokitansky-Kustner-Hauser syndrome (MRKH)).
3. Androgen insensitivity syndrome.
4. Delay in hypothalamic-pituitary maturation.
5. Olfacto-genital dysplasia, Kallmann syndrome.
6. Vaginal obstruction, cryptomenorrhea.
7. Receptor abnormalities for FSH, LH.
8. Specific forms of congenital adrenal hyperplasia
9. Swyer syndrome.
10. Galactosemia.
11. Aromatase deficiency
12. Prader-Willi syndrome
Secondary amenorrhoea
1. Hypothalamic-pituitary dysfunction, including exercise amenorrhoea, stress amenorrhoea, and eating disorders.
2. Hyperprolactinemia (elevated prolactin levels)
3. Polycystic ovary syndrome (PCO-S).
4. Androgen producing tumor (i.e arrhenoblastoma)
5. Intrauterine adhesions (Asherman's Syndrome).
6. Premature menopause.
7. Thyroid dysfunction.
8. Hemochromatosis.
Treatments vary based on the underlying condition. Key issues are problems of surgical correction if appropriate, estrogen therapy (if estrogen levels are low), and fertility.
Historically, the term amenorrhoea has often been used as a euphemism for "unwanted pregnancy" and many folk treatments for this condition are in fact abortifacients.
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