Oligomenorrhea

Etiology

Oligomenorrhea is often a sign of underlying disease. Following may be the causes of oligomenorrhea. 

• Polycystic ovarian disease[2]
• Androgen secreting tumor of the ovary[3]
• Androgen secreting tumor of the adrenal gland[4]
• Cushing syndrome
• Hyperthyroidism
• Prolactinomas
• Hypothalamic amenorrhea[5] 
• Pelvic inflammatory disease
• Asherman syndrome
• Uncontrolled diabetes mellitus
• Type-1 diabetes mellitus[6]
• Congenital adrenal hyperplasia[7]
• Non-classic congenital adrenal hyperplasia. 
• A side effect of oral contraceptive pills[8]
• Antipsychotics
• Antiepileptics
• Anatomic problems
• Primary ovarian insufficiency[9] 
• Exercising women with polycystic ovarian disease[10]

Epidemiology

The prevalence of oligomenorrhea is 13.5 percent in the general population.  A polycystic ovarian disease accounts for 4 to 10 percent of oligomenorrhea in women of reproductive age (from puberty to menopause). 11 to 44 percent of dancers and 6 to 60 percent of athletes report oligomenorrhea at some point in their life span.

History and Physical

History of oligomenorrhea includes a detailed history of menstruation, including duration of the menstrual cycle, the days of normal flow of menses in it, the number of pads used per day, the interval between two cycles, and the regularity of previous cycles. This information will give an idea about the amount of bleeding, the number of cycles in a year, and the regularity of menstrual cycles that will help to diagnose oligomenorrhea. Any irregularity of bleeding between menstrual cycles, hot flashes, and night sweats must be ruled out. The previous pattern of bleeding before the development of oligomenorrhea is important to know the baseline pattern of bleeding in the patient and the severity of change in that pattern.

Age of menarche, any sexual unprotected intercourse, abdomen pain, discharge, weight loss, are all necessary to determine the underlying cause. Any recent change in voice tone, hair growth, acne, blur vision, headaches, decreased libido, and production of milky discharge from nipples must be evaluated. Changes in bowel habits and skin also require evaluation.   

Birth history is essential in this regard. It may indicate infertility or any history of dilatation and curettage.  

In drug history, it is crucial to evaluate the use of birth control pills, antipsychotics, antiepileptics, and steroids.   

Family history may show Turner syndrome or polycystic ovarian disease in first degree relatives.[11]

PHYSICAL EXAMINATION  

Physical examination includes the following;  

• External examination.  
• Rectovaginal examination.   
• Vaginal speculum examination.  
• Abdomen examination.  

The external examination includes looking for any abnormal secondary sexual characteristics example, hair distribution, or clitoromegaly.  

The rectovaginal examination includes inserting a gloved finger lubricated with anesthetic gel to examine the walls of the vagina and to feel for any anatomic obstruction or abnormalities, tenderness in the abdomen, mass in adnexa or abdomen.

Vaginal speculum examination includes looking into the vagina and cervix with the use of a speculum. Look for any abnormal discharge, signs of inflammation, and growths.  

Abdomen examination includes inspection of the abdomen for ascites. Palpate the abdomen for masses and tenderness. Palpate the groin for inguinal lymphadenopathy. 

Evaluation

Labs to evaluate the cause of oligomenorrhea includes the following:  

Blood Tests

• FSH Levels; if increased, they show primary ovarian insufficiency.[12]  
• TSH levels; if decreased, then it shows hyperthyroidism.[13]  
• Prolactin levels; if increased, then prolactinoma may be the cause.[14]
• LH levels; the ratio of FSH\LH is useful in diagnosing polycystic ovarian disease.  
• Free testosterone levels; increased in congenital adrenal hyperplasia and polycystic ovarian disease.[15]
• 17 –OH levels; these are useful to diagnose congenital adrenal hyperplasia as a cause of oligomenorrhea.  
• Overnight dexamethasone suppression test; is done to diagnose Cushing syndrome as a cause of oligomenorrhea, especially if the patient presents with signs of this condition.
• HbA1C[6]

Investigations

• Ultrasound of abdomen and pelvis; it may indicate polycystic ovaries, signs of pelvic inflammation, and ascites.   
• CT scan is useful with suspicion of adnexal or adrenal masses.  
• MRI pituitary helps to confirm prolactinoma if prolactin levels increase.  
• Endocervical swabs are taken if there are signs of pelvic inflammatory disease.

Treatment / Management

Treatment of oligomenorrhea mainly depends on the underlying cause;  

Lifestyle Changes

Oligomenorrhea, when caused by low basal metabolic index and stress levels, can be dealt with behavior modification, diet, psychotherapy, and stress reduction techniques. Anovulation, when caused by obesity, can be managed with weight reduction.  

Hormonal Therapy

Birth control pills are often used to restore the regularity of the menstrual cycle, especially in Polycystic ovarian disease. They are safe to use, especially when the patient does not desire pregnancy.

Treating The Underlying Medical Conditions

If hyperthyroidism is the cause, then it is treated with antithyroid drugs, radioactive iodine or thyroidectomy. If the etiology is Cushing syndrome, then it is treated with medication that blocks excess cortisol overproduction example, ketoconazole, mitotane, and metyrapone. Prolactinomas, if small, can be treated with dopamine agonists example, bromocriptine, and cabergoline.  

Surgical Management

• Surgery may be necessary in the case of adnexal and adrenal tumors.
• Thyroidectomy may be necessary for hyperthyroidism.
• If prolactinoma is large enough to produce compressive symptoms, it may require surgical removal.

Differential Diagnosis

Menarche

Menarche is the first menstrual cycle in females. Its average age in the USA is 12.5 years. Girls may undergo initial anovulatory cycles that may cause light or irregular mensural flow that becomes regular overtime, which can be confused with oligomenorrhea, where initially women have established regular flow, and it gets lighter later on. 

Perimenopause

The irregular bleeding of perimenopause may be confused with oligomenorrhea, but mostly it is associated with accompanying sign and symptoms like hot flashes, vaginal dryness, night sweats, weight gain, mood changes and vaginal pain with intercourse whereas oligomenorrhea due to another medical condition will not be associated with such sign and symptoms.  

Irregular Bleeding 

Irregular bleeding may be confused with oligomenorrhea. Irregular bleeding is bleeding between cycles. It may indicate an endometrial polyp in premenopausal women or endometrial cancer in postmenopausal women. 

Pregnancy

It is crucial to make sure that cause of a delayed menstrual cycle is not a pregnancy. A pregnancy test is used for this purpose. A pregnancy test checks the urine or blood for a hormone called human chorionic gonadotropin (HCG). 

Pertinent Studies and Ongoing Trials

A small herbal medicine randomized controlled trial for oligomenorrhea and polycystic ovarian disease suggested that the individualized and standardized herbal medicine both have similar profiles in terms of safety and clinical effects in helping menstrual regularity.[16]

Prognosis

Oligomenorrhea itself is not a serious problem, but its underlying cause must be evaluated to avoid infertility. Moreover, if left untreated, it can increase the risk of endometrial hyperplasia and endometrial cancer. 

Complications

• Infertility: Untreated oligomenorrhea can lead to infertility in polycystic ovarian disease and primary ovarian insufficiency due to anovulation, impaired endometrium required for implantation in Asherman syndrome, fibrosis that occur as a result of pelvic inflammatory disease and metabolic derangement that occur in uncontrolled diabetes that makes pregnancy difficult. 
• Endometrial Hyperplasia: Oligomenorrhea that goes untreated for years can lead to endometrium proliferation and thus resulting in endometrial hyperplasia. 
• Endometrial Cancer: Endometrial hyperplasia is a precursor for endometrial cancer. Oral contraceptive pills that contain estrogen and progesterone are protective against endometrial cancer. 
• Osteoporosis: The main source of estrogen in the body is developing ovarian follicle that is lost due to anovulation in oligomenorrhea. This decrease in estrogen leads to osteoporosis. 
• Cardiovascular Problems: Estrogen is cardioprotective. Lack of estrogen due to anovulation leads to increase risk of myocardial ischemia. 
• Neuropsychiatric Complications: Anxiety, hallucination, delusion are psychiatric problems. Neurologic symptoms are involuntary movements in face and lips, anorexia, and asthenia.