Introduction

Oligomenorrhea is defined as irregular and infrequent menstrual cycles in women. Some variation in menstrual flow is normal during menarche, postpartum, or the perimenopausal period. However, if a woman reports menstrual cycles longer than 35 days or fewer than 4 to 9 cycles per year, it is considered oligomenorrhea. Normal menstrual flow should precede the development of oligomenorrhea.[1]

Etiology

The etiology of oligomenorrhea is diverse and may include endocrine disorders, medical conditions, eating disorders, lifestyle changes, or medication adverse effects.

Oligomenorrhea is often a symptom of an underlying condition. Common causes include: 

• Polycystic ovary syndrome (PCOS) [2]
• Androgen-secreting ovarian tumors [3]
• Androgen-secreting adrenal tumors [4]
• Cushing syndrome
• Hyperthyroidism
• Prolactinomas
• Hypothalamic amenorrhea[5] 
• Pelvic inflammatory disease
• Asherman syndrome
• Uncontrolled diabetes mellitus
• Type 1 diabetes [6]
• Congenital adrenal hyperplasia (classic and non-classic forms) [7]
• Adverse effects of oral contraceptive pills [8]
• Antipsychotic medications
• Antiepileptic medications
• Anatomical abnormalities of the reproductive tract
• Primary ovarian insufficiency [9] 
• PCOS in women who engage in excessive exercise [10]
• Hypothalamic amennhorea
• Anorexia nervosa
• Bulimia nervosa
• Lifestyle factors such as intense exercise, stress, and weight gain
• Surgical removal of the ovaries
• Radiation-induced ovarian damage

Epidemiology

The prevalence of oligomenorrhea in the general population is approximately 13.5%. PCOS accounts for 4% to 10% of cases of oligomenorrhea in women of reproductive age (from puberty to menopause). Among dancers, 11% to 44% report experiencing oligomenorrhea at some point in their lifetime, whereas 6% to 60% of athletes report the condition during their lifespan.

History and Physical

The history of oligomenorrhea should include a detailed account of the patient’s menstrual history, including the duration of the menstrual cycle, the number of days of normal menstrual flow, the number of pads used per day, the interval between cycles, and the regularity of previous cycles. This information provides insight into the volume of bleeding, the number of cycles per year, and the regularity of menstrual cycles, which are essential for diagnosing oligomenorrhea. Any irregular bleeding between cycles must be ruled out. Understanding the patient’s previous bleeding pattern is crucial for establishing a baseline and assessing the severity of any changes in that pattern.

The following factors should be assessed to help identify the underlying cause of oligomenorrhea: age at menarche, history of unprotected sexual intercourse, abdominal pain, abnormal vaginal discharge, and unintended weight loss. Additional symptoms to evaluate include recent changes in voice, excessive hair growth, acne, blurred vision, headaches, decreased libido, and galactorrhea (milky nipple discharge). A history of dilation and curettage procedures should also be noted. Changes in bowel habits and skin appearance may provide further diagnostic clues and should not be overlooked.

When taking a drug history, it is important to assess the use of birth control pills, antipsychotics, antiepileptics, and corticosteroids, as these may contribute to menstrual irregularities. A family history should also be reviewed for conditions such as Turner syndrome or PCOS, particularly in first-degree relatives.[11]

Physical Examination

The physical examination should include:

• External genital examination
• Rectovaginal examination
• Abdominal examination

The external examination should assess for any abnormal secondary sexual characteristics, such as irregular hair distribution or clitoromegaly.

The rectovaginal examination involves inserting a gloved, lubricated finger to assess the vaginal walls for any anatomical obstructions or abnormalities. This also helps identify tenderness in the abdomen or any masses in the adnexa or abdominal region.

The vaginal speculum examination involves inspecting the vagina and cervix using a speculum. During this examination, clinicians should check for any abnormal discharge, signs of inflammation, or the presence of growths.

An abdominal examination involves inspecting the abdomen for signs of ascites. The examiner should palpate the abdomen to assess for masses and tenderness, as well as palpate the groin to check for inguinal lymphadenopathy.

Evaluation

A basic lab panel should be ordered to evaluate oligomenorrhea, as it will help guide further investigation given the various potential underlying causes of the condition. The labs to assess the underlying cause of oligomenorrhea include: 

Lab Panels

• Follicle-stimulating hormone (FSH) levels: Increased levels may indicate primary ovarian insufficiency.[12]
• Thyroid-stimulating hormone (TSH) levels: Decreased levels suggest hyperthyroidism.[13]
• Prolactin levels: Elevated levels may indicate prolactinoma as the cause.[14]
• Luteinizing hormone (LH) levels: The FSH:LH ratio helps diagnose PCOS.
• Free testosterone levels: Increased levels may be seen in congenital adrenal hyperplasia and PCOS.[15]
• 17-OH levels: These are useful for diagnosing congenital adrenal hyperplasia as a cause of oligomenorrhea. 
• Dexamethasone suppression test: An overnight dexamethasone suppression test is performed to diagnose Cushing syndrome, especially in patients presenting with signs of the condition.
• Cortisol and HbA1C levels.[6]

Investigations

• Ultrasound of the abdomen and pelvis: This imaging technique can indicate polycystic ovaries, signs of pelvic inflammation, and ascites.
• Computed tomography (CT) scan: A CT scan is useful when adnexal or adrenal masses are suspected.
• Magnetic resonance imaging (MRI): An MRI scan helps confirm prolactinoma in cases of elevated prolactin levels.
• Endocervical swabs: These should be taken if signs of pelvic inflammatory disease are present.

Treatment / Management

The treatment of oligomenorrhea primarily depends on addressing the underlying cause. Therefore, obtaining a thorough history, conducting a detailed physical examination, and ordering the relevant lab panel to guide management is crucial.

Lifestyle Changes

When oligomenorrhea is caused by a low basal metabolic index or high stress levels, it can be managed through behavior modification, dietary changes, psychotherapy, and stress reduction techniques. Weight reduction is an effective management strategy for anovulation associated with obesity.

Hormonal Therapy

Birth control pills are commonly used to restore regularity to the menstrual cycle, particularly in cases of PCOS. They are safe for use, especially in patients who do not desire pregnancy.

Management of Underlying Medical Conditions

When oligomenorrhea is secondary to an underlying medical disorder, targeted treatment is essential.

• Hyperthyroidism is managed with antithyroid medications, radioactive iodine therapy, or thyroidectomy.
• Cushing syndrome is treated with medications that suppress cortisol production, such as ketoconazole, mitotane, or metyrapone.
• Prolactinomas, if small, are typically managed with dopamine agonists, such as bromocriptine or cabergoline.

Surgical Management

Surgery may be indicated in specific cases, as mentioned below.

• Adnexal or adrenal tumors may require surgical excision.
• Thyroidectomy may be needed for the treatment of hyperthyroidism.
• Prolactinomas that are large enough to cause compressive symptoms may require surgical removal.

Differential Diagnosis

Menarche

Menarche refers to the onset of the first menstrual cycle in females, with the average age in the United States being approximately 12.5 years. During this time, girls may experience initial anovulatory cycles, which can lead to light or irregular menstrual flow that often becomes regular over time. This can be confused with oligomenorrhea, where women initially have established regular menstrual cycles that later become lighter and more irregular.

Perimenopause

The irregular bleeding of perimenopause may be confused with oligomenorrhea. However, perimenopausal bleeding is typically accompanied by other signs and symptoms such as hot flashes, vaginal dryness, night sweats, weight gain, mood changes, and vaginal pain during intercourse. In contrast, oligomenorrhea caused by other medical conditions is usually not associated with these symptoms.

Irregular Bleeding 

Irregular bleeding can be mistaken for oligomenorrhea, but it refers to bleeding that occurs between menstrual cycles rather than infrequent periods. In premenopausal women, it may suggest the presence of an endometrial polyp, while in postmenopausal women, it could be a sign of endometrial cancer.

Pregnancy

Ruling out pregnancy is a critical first step when evaluating a delayed menstrual cycle. A pregnancy test, which detects human chorionic gonadotropin (hCG) in urine or blood, helps confirm or exclude this possibility.

Pertinent Studies and Ongoing Trials

A small randomized controlled trial on herbal medicine for oligomenorrhea and PCOS suggested that both individualized and standardized herbal treatments have similar safety profiles and clinical effects in promoting menstrual regularity.[16]

Prognosis

Oligomenorrhea itself is not typically a severe condition, but its underlying cause must be assessed to prevent potential infertility. If left untreated, it can also increase the risk of endometrial hyperplasia and endometrial cancer. 

Complications

Untreated oligomenorrhea can lead to several complications affecting various systems in the body.

• Infertility: Untreated oligomenorrhea can lead to infertility in conditions such as PCOS and primary ovarian insufficiency due to anovulation. Infertility can also impair the endometrium necessary for implantation in Asherman syndrome, cause fibrosis resulting from pelvic inflammatory disease, and contribute to metabolic derangements seen in uncontrolled diabetes, all of which can make pregnancy more difficult. 
• Endometrial hyperplasia: Untreated oligomenorrhea over an extended period can lead to endometrial proliferation, resulting in endometrial hyperplasia.
• Endometrial cancer: Endometrial hyperplasia can progress to endometrial cancer. Oral contraceptive pills containing estrogen and progesterone offer protective effects against the development of endometrial cancer. 
• Osteoporosis: Estrogen, primarily produced by developing ovarian follicles, is reduced due to anovulation in oligomenorrhea. This decrease in estrogen levels can lead to osteoporosis.
• Cardiovascular problems: Estrogen has a cardioprotective effect. The absence of estrogen due to anovulation increases the risk of myocardial ischemia.
• Neuropsychiatric complications: Psychiatric issues associated with oligomenorrhea include anxiety, hallucinations, and delusions. Neurological symptoms may involve involuntary facial and lip movements, anorexia, and asthenia.

Deterrence and Patient Education

Patients should track the date of their menstrual cycle each month and monitor any irregularities or changes in the amount of bleeding during their menstrual cycles. Any sudden changes should be noted. In addition, patients need to understand the normal physiology of the menstrual cycle and when to consult a doctor. A woman should contact a gynecologist if she experiences a gap of more than 35 days without a period. This education helps patients seek timely medical advice when needed.

When using birth control pills to maintain menstrual cycle regularity in oligomenorrhea, patients should be counseled by their healthcare providers on the importance of taking their medication consistently at the same time every day. This ensures optimal efficacy and helps prevent withdrawal bleeding due to noncompliance with drugs. Patients should also understand that pregnancy is unlikely while using birth control pills. If pregnancy is desired, alternative treatment options should be discussed and explored with their gynecologist.

Enhancing Healthcare Team Outcomes

A multidisciplinary team approach is essential to improving outcomes in patients with oligomenorrhea. This healthcare team may include a gynecologist to address the underlying cause, a nutritionist to help manage weight in patients experiencing obesity, and a psychotherapist to support women coping with the mental pressure of delayed or inability to conceive. An endocrinologist is also crucial for managing conditions such as diabetes mellitus and hyperthyroidism, which may contribute to oligomenorrhea. Effective coordination between a gynecologist and an endocrinologist is key to improving outcomes, particularly in enhancing fertility in women when desired.

Review Questions

• Access free multiple choice questions on this topic.
• Click here for a simplified version.
• Comment on this article.

References

1.

Hennegan J, Brooks DJ, Schwab KJ, Melendez-Torres GJ. Measurement in the study of menstrual health and hygiene: A systematic review and audit. PLoS One. 2020;15(6):e0232935. [PMC free article: PMC7272008] [PubMed: 32497117]

2.

Gurbuz AS, Gode F. Dydrogesterone-primed ovarian stimulation is an effective alternative to gonadotropin-releasing hormone antagonist protocol for freeze-all cycles in polycystic ovary syndrome. J Obstet Gynaecol Res. 2020 Aug;46(8):1403-1411. [PubMed: 32500628]

3.

Kalashnikova MF, Likhodey NV, Tiulpakov AN, Fedorova EV, Bryunin DV, Bakhvalova AA, Glushakova MA, Smirnova SA, Fadeyev VV. [Virilizing ovarian tumor: the challenges of differential diagnosis]. Probl Endokrinol (Mosk). 2019 Dec 25;65(4):273-277. [PubMed: 32202730]

4.

Di Dalmazi G. Hyperandrogenism and Adrenocortical Tumors. Front Horm Res. 2019;53:92-99. [PubMed: 31499503]

5.

Pinelli G, Tagliabue A. Nutrition and fertility. Minerva Gastroenterol Dietol. 2007 Dec;53(4):375-82. [PubMed: 18043554]

6.

Deltsidou A, Lemonidou C, Zarikas V, Matziou V, Bartsocas CS. Oligomenorrhoea in adolescents with type 1 diabetes mellitus: relationship to glycaemic control. Eur J Obstet Gynecol Reprod Biol. 2010 Nov;153(1):62-6. [PubMed: 20702019]

7.

Engberg H, Möller A, Hagenfeldt K, Nordenskjöld A, Frisén L. Identity, Sexuality, and Parenthood in Women with Congenital Adrenal Hyperplasia. J Pediatr Adolesc Gynecol. 2020 Oct;33(5):470-476. [PubMed: 32473322]

8.

Banh C, Rautenberg T, Duijkers I, Borenzstein P, Monteil C, Levy-Gompel D, Klipping C, Scherrer B, Glasier A. The effects on ovarian activity of delaying versus immediately restarting combined oral contraception after missing three pills and taking ulipristal acetate 30 mg. Contraception. 2020 Sep;102(3):145-151. [PubMed: 32474062]

9.

Bensing S, Giordano R, Falorni A. Fertility and pregnancy in women with primary adrenal insufficiency. Endocrine. 2020 Nov;70(2):211-217. [PubMed: 32472424]

10.

Awdishu S, Williams NI, Laredo SE, De Souza MJ. Oligomenorrhoea in exercising women: a polycystic ovarian syndrome phenotype or distinct entity? Sports Med. 2009;39(12):1055-69. [PubMed: 19902985]

11.

Dabrowski E, Jensen R, Johnson EK, Habiby RL, Brickman WJ, Finlayson C. Turner Syndrome Systematic Review: Spontaneous Thelarche and Menarche Stratified by Karyotype. Horm Res Paediatr. 2019;92(3):143-149. [PubMed: 31918426]

12.

Siristatidis C, Pouliakis A, Sergentanis TN. Special characteristics, reproductive, and clinical profile of women with unexplained infertility versus other causes of infertility: a comparative study. J Assist Reprod Genet. 2020 Aug;37(8):1923-1930. [PMC free article: PMC7467999] [PubMed: 32504303]

13.

Colella M, Cuomo D, Giacco A, Mallardo M, De Felice M, Ambrosino C. Thyroid Hormones and Functional Ovarian Reserve: Systemic vs. Peripheral Dysfunctions. J Clin Med. 2020 Jun 01;9(6) [PMC free article: PMC7355968] [PubMed: 32492950]

14.

Kalsi AK, Halder A, Jain M, Chaturvedi PK, Sharma JB. Prevalence and reproductive manifestations of macroprolactinemia. Endocrine. 2019 Feb;63(2):332-340. [PubMed: 30269265]

15.

Kostopoulou E, Anagnostis P, Bosdou JK, Spiliotis BE, Goulis DG. Polycystic ovary Syndrome in Adolescents: Pitfalls in Diagnosis and Management. Curr Obes Rep. 2020 Sep;9(3):193-203. [PubMed: 32504286]

16.

Lai L, Flower A, Prescott P, Wing T, Moore M, Lewith G. Standardised versus individualised multiherb Chinese herbal medicine for oligomenorrhoea and amenorrhoea in polycystic ovary syndrome: a randomised feasibility and pilot study in the UK. BMJ Open. 2017 Feb 03;7(2):e011709. [PMC free article: PMC5293993] [PubMed: 28159846]

Disclosure: Yumna Riaz declares no relevant financial relationships with ineligible companies.

Disclosure: Utsav Parekh declares no relevant financial relationships with ineligible companies.