Overview

Hormones play a vital role in developing and regulating women's reproductive functions, particularly the menstrual cycle.¹ This cycle is a hormone-driven, rhythmic process that involves monthly bleeding. Its onset is closely linked to puberty, which marks the beginning of reproductive maturity. The first menstrual period, known as menarche, usually occurs between 11 and 14 years old. Following menarche, the menstrual cycle typically becomes regular within 1 to 1.5 years. Menstrual disorders are common among adolescent girls, affecting approximately 50% of them. These issues may include amenorrhea, dysmenorrhea, premenstrual syndrome (PMS), irregular uterine bleeding, and polycystic ovary syndrome(PCOS). While many of these conditions are mild, such as occasional changes in the duration or flow of periods, some cases, especially those involving heavy uterine bleeding, can be severe enough to require hospitalisation.²

Key hormones involved

1. Estrogen and progesterone- these hormones regulate the menstrual cycle. Malfunctioning of these hormones can lead to missed periods, heavy bleeding, or irregular menstrual periods
2. Follicle-stimulating hormone(FSH) and luteinizing hormone (LH) help in controlling ovulation, which may get disrupted if the hormonal imbalances occur
3. Thyroid hormones(T3,T4,TSH)- dysfunction of these hormones(hypothyroidism and hyperthyroidism) can lead to menstrual irregularities
4. Prolactin- raised level of this particular hormone(due to pituitary gland malfunction) can cause the stoppage of menstruation
5. Androgens(testosterone)- abnormal elevation of this hormone in blood causes excessive hair(hirsutism), irregular or absence of menstruation or polycystic ovary disease(PCOD)

Common causes of hormonal imbalances leading to menstrual irregularities

• Stress
• Pituitary gland disorder
• Thyroid disorders
• Obesity
• Certain medications( OCPs, antipsychotics)
• Excessive exercise
• Low body fat
• PCOS(Polycystic ovary syndrome)³

Different types of menstrual irregularities

Amenorrhea refers to the complete absence of menstruation from birth and should be evaluated if a girl has not started menstruating by age 15 or within three years of breast development (thelarche). Secondary amenorrhea refers to the absence of menstruation for three consecutive months in individuals with previously regular cycles, or for six months in those whose cycles were previously irregular. When assessing amenorrhea, clinicians typically categorise potential causes into groups such as abnormalities of the outflow tract, primary ovarian insufficiency, disorders of the hypothalamus or pituitary gland, other endocrine conditions, complications of chronic illnesses, physiological factors, or external (induced) influences.⁴

Dysmenorrhea occurs in 50% to 90% of adolescent girls and women of reproductive age and is a leading cause of absenteeism. Secondary dysmenorrhea as a result of endometriosis, pelvic anatomic abnormalities, or infection may present with progressive worsening of pain, abnormal uterine bleeding, vaginal discharge, or dyspareunia(painful intercourse).⁵

Premenstrual disorders affect up to 12% of women and can occur at any point between menarche and menopause. Research indicates that estrogen and progesterone levels fluctuate throughout the menstrual cycle and are likely responsible for triggering these symptoms. Around 80% of women experience at least one physical or psychological symptom during the luteal phase—the period between ovulation and the onset of menstruation. However, these symptoms do not significantly interfere with daily functioning for most.⁶

Abnormal uterine bleeding (AUB) is a broad term that describes irregularities in the menstrual cycle involving the parameters of frequency, regularity, duration, and volume of flow outside of pregnancy in reproductive-aged women. Approximately one-third of women will experience abnormal uterine bleeding (AUB) at some point in their lives. Irregularities most commonly occur during menarche and perimenopause. A typical menstrual cycle has a frequency from 24 to 38 days and lasts between 2 to 7 days. A total blood volume loss of 5 to 80 mL takes place during this phase. Any deviation from these normal parameters leads to AUB.⁷

Menorrhagia (also known as heavy menstrual bleeding) can disrupt daily routines, negatively impact quality of life, and contribute to anaemia in approximately two-thirds of women who experience excessive blood loss (defined as 80 mL or more per cycle). Disruptions in prostaglandin regulation are thought to be linked to idiopathic menorrhagia, as well as to heavy bleeding associated with fibroids, adenomyosis, or the use of intrauterine devices (IUDs). ⁸

Symptoms

• Irregular or missed periods
• Very heavy or light bleeding during menstruation
• Severe premenstrual syndrome(PMS) - severe physical and emotional upheaval one or two weeks before the onset of the menstrual cycle, which subsides once menstruation starts.
• Acne, excessive hair formation(hirsutism), and changes in your weight.
• Fatigue, mood changes, changes in libido
• Vaginal atrophy
• Vaginal dryness
• Hair loss
• Hot flushes³

Treatment and management

1. Visit your doctor: You might be advised to undertake certain blood tests to detect the hormone levels, and then you will be provided with medications as required. Hormone replacement therapy is advised if you have lower-than-normal hormone levels. In cases of hypothyroidism, synthetic thyroid hormone pills are prescribed. Excess of prolactin can cause prolactinoma, a benign, cancerous tumour that can be managed by your doctor prescribing suitable medications
2. Lifestyle modifications: You should have a healthy and balanced diet, manage your weight, and exercise regularly to reduce stress and regulate hormones in your blood
3. You should quit smoking and tobacco products as soon as possible³

FAQs

What is considered a menstrual irregularity?

A menstrual irregularity involves changes in the frequency, duration, flow, or symptoms of a woman’s menstrual cycle. Common forms include missed periods (amenorrhea), painful periods (dysmenorrhea), very heavy periods (menorrhagia), and irregular bleeding patterns (abnormal uterine bleeding).

What are the key hormones responsible for regulating the menstrual cycle?

The main hormones involved include:

• Estrogen and Progesterone regulate the menstrual cycle
• FSH and LH control ovulation
• Thyroid hormones (T3, T4, TSH) imbalances can cause irregular periods
• Prolactin elevated levels can stop menstruation
• Androgen (like testosterone) excess can lead to PCOS, hirsutism, and irregular cycles

What causes hormonal imbalances that affect menstruation?

• Stress
• Pituitary gland disorders
• Thyroid dysfunction
• PCOS
• Obesity or low body fat
• Certain medications (e.g., oral contraceptives, antipsychotics)
• Excessive physical activity

What is amenorrhea, and should I see a doctor?

Amenorrhea is the absence of menstruation. Primary amenorrhea should be investigated if periods haven’t started by age 15 or within 3 years of breast development. Secondary amenorrhea is the absence of periods for 3 months in someone with regular cycles, or 6 months in those with irregular cycles.

What is dysmenorrhea, and how is it treated?

Dysmenorrhea is painful menstruation, there are two main types. Primary dysmenorrhea is common and usually not linked to other diseases. Secondary dysmenorrhea may be caused by conditions like endometriosis or infections. Treatment may involve pain relievers, hormonal therapy, or addressing underlying conditions.

What is premenstrual syndrome (PMS)?

PMS includes emotional and physical symptoms like mood swings, bloating, or fatigue that occur one to two weeks before menstruation. While common, symptoms are usually mild and do not interfere significantly with daily life.

What is considered abnormal uterine bleeding (AUB)?

AUB is any bleeding that deviates from standard cycle patterns (24–38 days, lasting 2–7 days, with 5–80 mL of blood loss). It’s most common during menarche and perimenopause and should be evaluated to determine the cause.

What are the signs that may indicate a hormonal imbalance?

• Irregular or missed periods
• Very heavy or light menstrual flow
• Severe PMS symptoms
• Acne, hirsutism, or hair loss
• Fatigue, mood swings, or hot flushes
• Vaginal dryness or changes in libido

Can lifestyle changes help manage hormonal imbalances?

Yes. A healthy diet, regular exercise, stress management, maintaining a healthy weight, and avoiding smoking or tobacco products can help regulate hormone levels and improve menstrual regularity.

When should I see a doctor for menstrual irregularities?

Consult a doctor if you have:

• Missed periods for several months
• Experienced very heavy or painful bleeding
• Noticed unusual symptoms like severe PMS, hair growth, or acne
• Irregular cycles that affect your daily life

An early diagnosis and treatment can prevent complications and improve overall health.

Summary

Irregular menstrual cycles are a common issue affecting women globally and can stem from various causes, including hormonal disruptions and structural abnormalities. Ultrasound imaging has become a valuable diagnostic tool for evaluating various gynaecological conditions. Hormonal imbalances can be treated to some extent by changing your lifestyle and quitting any oral habits that are disastrous to health. Any menstrual abnormalities should be brought to the immediate attention of your health provider for early intervention and timely management, which ultimately aids in leading a healthy life.