Female menstrual cycle normally comprises a 28 to 30-day cycle, which contains 2 phases, the proliferative phase, and secretory phase. At the end of the cycle, the uterine lining starts shedding off which is a normal phenomenon of female menstruation.
The absence of menstruation during the female during the reproductive ages of approximately 12 to 49 years is known as amenorrhea.
Primarily amenorrhea is classified into 2 types determined by pathogenesis.Primary amenorrhea is the absence of initiation of menses, and secondary amenorrhea is an absence of menses in a previously normal menstruating female. There are many other types of classification of amenorrhea based on the anatomy of female reproductive organs, but this is the most accepted form of classifying the causes of amenorrhea.
Amenorrhea is not life-threatening, but the loss of the menstrual cycle has been associated with a high risk of hip and wrist fractures.
The absence of menses in a female of reproductive age is related to the disturbance of normal hormonal, physiological mechanism or female anatomic abnormalities. The normal physiological mechanism works by balancing hormones and providing feedback between the hypothalamus, pituitary, ovaries, and uterus.
During normal female menstruation cycle, gonadotropin-releasing hormone (GnRH) is released from hypothalamus, and it works on pituitary to release follicle-stimulating hormone (FSH) and luteinizing hormone (LH) and these 2 hormones from pituitary act on ovaries and ovaries finally make estrogen and progesterone to work on the uterus to carry out the follicular and secretory phase of menstrual cycle. Any defect at any level of this normal physiology of female can cause amenorrhea.
On other hand, deviation from the normal anatomy of reproductive organs of a female can also cause amenorrhea.
During history and physical examination, clinicians first need to ask about the age of a patient and at what age the patient started menses at puberty (menarche). This information is important to determine and differentiate between primary and secondary amenorrhea. If the patient was not menstruating at all, then it must be primary amenorrhea. All other cases will be secondary amenorrhea.
After chronological age, the most important thing to determine is the psychosocial age of the patient, as well as their intelligence quotient (IQ) to rule out any chromosomal cause of primary amenorrhea. After that, clinicians should inquire about the other aspects of growth like breast bud development, because an absence of breast bud by the age of 13 to 14 years indicates estradiol deficiency, and there is a need for further investigation.
To rule out secondary amenorrhea, physicians need to determine the time frame of the absence of menses in the previously normal menstruating female. The most important cause of secondary amenorrhea is pregnancy, so it should be ruled out first. They should then ask about previous surgeries for Asherman syndrome.
A history of night sweats, sleep disturbance, and hot flushes for premature ovarian failure, history of chemotherapy, and radiation therapy for neoplasm should be obtained because these can also cause ovarian failure in young females. Polycystic ovary syndrome (PCOS) should be ruled out in accordance with Rotterdam criteria.
Vision test and sense of smell should be performed to for pituitary adenoma and Kallman syndrome. A history of medication is very important because antipsychotics are one of the most common causes of high prolactin levels which lead to the amenorrhea. The use of contraception, cocaine, opioids, antiepileptics can cause failure of menstruation to occur, dieting, strenuous exercise, history of weight loss, and anorexia nervosa can be determined by proper history taking to ascertain the cause of amenorrhea.
History of neurosarcoidosis, hemochromatosis, and presence of any chronic illness should be detected to determine the exact reason as these diseases greatly effect the hypothalamic-pituitary axis which plays a vital role in controlling of the female menstrual cycle.
Physical examination includes the general physical examination which can be used to determine causes like malnutrition or hepatomegaly. The examination also should include:
Acanthosis nigricans (skin condition) can also provide the clue for PCOS. Examing the breasts, pubic hair, and the clitoral index is also an important part of the physical examination in the female with amenorrhea. Turner syndrome can be ruled out through a normal chest examination. Clinicians should also perform a fundal examination to rule out pregnancy and a vaginal examination to check for hematocolpos in an imperforate hymen.
The evaluation should include:
Treatment mainly depends on the cause of amenorrhea. If the cause of amenorrhea is estrogen deficiency, estrogen can be administered. If amenorrhea is due to malnutrition, proper diet plan can cure the patient successfully. For anorexia nervosa and stress-induced amenorrhea, cognitive behavioral therapy and SSRIs can help. Dopamine agonist drugs like cabergoline can treat prolactinoma, and if large, surgery can provide a full cure. The appropriate surgical procedure can treat anatomical causes of amenorrhea. PCOS can be handled by combined oral contraceptives and metformin. SSRI can treat Stress-induced hypothalamic amenorrhea.
The causes of amenorrhea are diverse, and a multidisciplinary approach is required. Patients must be followed up for several years to ensure that the menstrual cycle has returned.