EXPERT GUIDE TO MENSTRUAL DISORDERS

Menstruation, also known as a woman’s period, is a natural process that occurs in the female reproductive system. It involves the shedding of the uterine lining, which is then expelled from the body through the vagina. The physiology of menstruation is a complex process that is regulated by hormones and involves several stages.

1. Menstrual Cycle: The menstrual cycle is controlled by hormones such as estrogen and progesterone, which are produced by the ovaries. The cycle typically lasts around 28 days and is divided into three phases: the follicular phase, ovulation, and the luteal phase.
2. Follicular Phase: During this phase, which lasts about 14 days, the pituitary gland releases follicle-stimulating hormone (FSH), which stimulates the growth of ovarian follicles. These follicles contain eggs, and as they grow, they produce estrogen.
3. Ovulation: Around day 14 of the menstrual cycle, a surge in luteinizing hormone (LH) triggers ovulation. This is when an egg is released from one of the mature follicles in the ovary and moves into the fallopian tube.
4. Luteal Phase: After ovulation, the empty follicle transforms into a structure called the corpus luteum, which produces progesterone. This hormone helps prepare the uterine lining for a potential pregnancy.
5. Menstruation: If fertilization does not occur, estrogen and progesterone levels drop towards the end of the menstrual cycle. This drop in hormone levels causes the blood vessels in the uterine lining to constrict, leading to its breakdown and shedding as menstrual blood.

The process of menstruation is essential for reproductive health and fertility in women. It serves to prepare the uterus for potential pregnancy each month by shedding and renewing its lining.

Definition and Classification of Abnormal Uterine Bleeding

Abnormal Uterine Bleeding (AUB) is defined as bleeding from the uterus that is abnormal in frequency, duration, or amount, and is not related to pregnancy.

AUB can be classified into several categories, including:

1. Ovulatory AUB: Ovulatory AUB is caused by hormonal imbalances, particularly an excess of estrogen, which leads to irregular ovulation and subsequent bleeding.
2. Anovulatory AUB: Anovulatory AUB is caused by a lack of ovulation, resulting in unopposed estrogen production and irregular bleeding.
3. AUB-C (Coagulopathy): AUB-C is caused by bleeding disorders, such as von Willebrand disease or platelet function disorders, which affect blood clotting and lead to abnormal bleeding.
4. AUB-P (Polyp): AUB-P is caused by the presence of uterine polyps, which are benign growths that can cause irregular bleeding.
5. AUB-A (Adenomyosis): AUB-A is caused by adenomyosis, a condition in which tissue similar to the lining of the uterus grows into the muscle of the uterus, leading to heavy and prolonged bleeding.
6. AUB-E (Endometrial): AUB-E is caused by endometrial polyps, hyperplasia, or cancer, which can cause abnormal bleeding.
7. AUB-M (Miscellaneous): AUB-M includes other causes of abnormal bleeding, such as thyroid disorders, polycystic ovary syndrome (PCOS), and certain medications.

Causes of Abnormal Uterine Bleeding (AUB)

The causes of AUB can be broadly classified into two categories: hormonal and non-hormonal.

1. Hormonal Causes

Hormonal imbalances, particularly an excess of estrogen or a lack of progesterone, can cause AUB.

• Polycystic ovary syndrome (PCOS): a hormonal disorder that can cause irregular ovulation and bleeding.
• Thyroid disorders: hypothyroidism or hyperthyroidism can affect hormone levels and lead to AUB.
• Adrenal disorders: certain adrenal disorders, such as congenital adrenal hyperplasia, can cause hormonal imbalances and AUB.

2. Non-hormonal causes

Non-hormonal causes of AUB include:

• Uterine polyps: benign growths that can cause bleeding.
• Adenomyosis: a condition in which tissue similar to the lining of the uterus grows into the muscle of the uterus.
• Endometrial polyps: benign growths that can cause bleeding.
• Endometrial hyperplasia: a condition in which the lining of the uterus grows excessively.
• Endometrial cancer: a type of cancer that can cause abnormal bleeding.
• Bleeding disorders: such as von Willebrand disease or platelet function disorders.
• Medications: certain medications, such as anticoagulants or hormone replacement therapy, can cause AUB.

Dysfunctional Uterine Bleeding (DUB)

Dysfunctional uterine bleeding (DUB) is a common gynecological condition characterized by abnormal uterine bleeding in the absence of any identifiable organic pathology. DUB can occur at any age but is most commonly seen in women during their reproductive years. There are various types of DUB, including anovulatory bleeding, ovulatory bleeding, and irregular shedding patterns. Anovulatory bleeding occurs when ovulation does not take place, leading to unopposed estrogen stimulation of the endometrium and subsequent irregular bleeding. Ovulatory bleeding, on the other hand, occurs when ovulation takes place but there is inadequate progesterone production, resulting in abnormal bleeding patterns. Irregular shedding patterns refer to unpredictable and erratic bleeding episodes that do not follow a regular menstrual cycle.

The causes of DUB are multifactorial and can include hormonal imbalances, thyroid disorders, polycystic ovary syndrome (PCOS), uterine fibroids, endometrial polyps, adenomyosis, pelvic inflammatory disease (PID), coagulation disorders, and certain medications such as anticoagulants or hormonal contraceptives. Diagnosis of DUB involves a thorough medical history taking, physical examination, pelvic ultrasound to evaluate the uterus and ovaries, blood tests to assess hormone levels (such as thyroid function tests), and sometimes endometrial biopsy to rule out any underlying pathology.

Overall, the management of DUB depends on the underlying cause and may include hormonal therapy (such as oral contraceptives or progestins), nonsteroidal anti-inflammatory drugs (NSAIDs) for symptomatic relief, dilation and curettage (D&C) in cases of severe bleeding or to obtain tissue samples for further evaluation, or surgical interventions like endometrial ablation or hysterectomy in refractory cases.

The pathophysiology of DUB

The pathophysiology of DUB is complex and multifactorial, involving disruptions in the normal hormonal regulation of the menstrual cycle.

One of the key factors contributing to DUB is an imbalance in the levels of estrogen and progesterone, which are the two main hormones that regulate the menstrual cycle. Estrogen stimulates the growth of the endometrium, while progesterone helps maintain its stability. In cases of DUB, there may be inadequate production of progesterone relative to estrogen, leading to prolonged and heavy menstrual bleeding.

Another factor that can contribute to DUB is anovulation, which occurs when a woman fails to release an egg during her menstrual cycle. Without ovulation, there is a lack of progesterone production, resulting in irregular shedding of the endometrial lining and abnormal bleeding patterns.

Other potential causes of DUB include thyroid disorders, polycystic ovary syndrome (PCOS), obesity, stress, and certain medications such as anticoagulants or hormonal contraceptives. These conditions can disrupt the normal hormonal balance and lead to abnormal uterine bleeding.

Roles of Eicosanoids

Eicosanoids are signaling molecules derived from polyunsaturated fatty acids that play a crucial role in regulating inflammation, vascular tone, and hemostasis. In the context of DUB, eicosanoids such as prostaglandins and thromboxanes are involved in the modulation of uterine contractility, vascular permeability, and platelet aggregation. Imbalances in the production of these eicosanoids can lead to aberrant uterine bleeding patterns seen in DUB.

Prostaglandins, particularly prostaglandin F2α (PGF2α) and prostacyclin (PGI2), are known to influence uterine contractility and vascular tone. Increased levels of PGF2α can cause vasoconstriction and myometrial contractions, leading to heavy menstrual bleeding commonly observed in DUB. On the other hand, PGI2 acts as a vasodilator and inhibits platelet aggregation, contributing to the maintenance of normal menstrual flow.

Thromboxanes, such as thromboxane A2 (TXA2), are potent vasoconstrictors and platelet aggregators that promote hemostasis. Dysregulation of TXA2 synthesis can result in excessive vasoconstriction and platelet activation, leading to abnormal bleeding patterns in DUB.

Overall, the dysregulation of eicosanoid production in the endometrium contributes to the pathogenesis of DUB by affecting uterine contractility, vascular integrity, and hemostasis. Understanding the role of eicosanoids in DUB may provide insights into potential therapeutic targets for managing abnormal uterine bleeding.