Understanding Menstrual Cycle Variability and Disorders
Author: Dr. med. univ. Martin Kiebler
At theblood, one of the fundamental things we're committed to is closing the gender data gap in healthcare. One crucial aspect of this lies in understanding the menstrual cycle and its various disorders that can disrupt it. Beyond being a monthly occurrence, menstruation is a complex biological process that reflects a woman's overall health. After you have read this article, you will have a good knowledge of how the menstrual cycle functions and what potential bleeding patterns, and menstrual disorders exist. We will also touch on diagnostic methods and the underlying causes of these disorders.
Understanding the Mechanics of Your Menstrual Cycle
The menstrual cycle is a hormonally controlled process that allows conception between menarche (the first menstrual period) and menopause (the cessation of menstrual cycles) by inducing the ovaries to expel an egg cell, as well as preparing the endometrium (inner layer of the uterus) for potential implantation.
The menstrual cycle typically lasts 25 – 31 days, with variability mainly occurring during the first half, particularly during the development of egg cells. The second half consistently lasts 14 – 15 days. Menstruation usually lasts 3 – 7 days, with an average blood loss of 30 – 60 ml.
That's more than half a litre per year!
1st Half of the Cycle (Day 1 - 14) = Proliferation- & Follicular Phase
Menstruation (Day 1 - 4) begins with the shedding of the functional endometrial layer. The proliferation phase (Day 4 - 15) follows, driven by estrogen.
In the follicular phase, multiple follicles (with egg cells within them) in the ovary mature under the influence of FSH (Follicle-Stimulating Hormone) a hormone released by the brain. A dominant follicle is selected, leading to increased estrogen production and an LH/FSH peak that triggers ovulation.
2nd Half of the Cycle (Day 14 - 28) = Luteal Phase
Ovulation occurs around day 14, followed by the formation of the corpus luteum, which produces progesterone. In the absence of pregnancy, the corpus luteum regresses.
Progesterone induces endometrial differentiation, preparing for possible implantation. Without pregnancy, progesterone levels decline, leading to functional endometrial necrosis and menstruation.
Around day 28, the shedding of endometrial tissue will start and with this, a new cycle has begun.
[Check out this blog post HERE for more information on the menstrual cycle and what takes place].
Figure 1. Primary hormonal fluctuations, and the events occurring within both the ovarian and uterine cycle of the menstrual cycle.
The menstrual cycle encompasses distinct phases, which are categorized by events in the ovaries (ovarian cycle) or the uterus (uterine cycle). The ovarian cycle comprises the follicular phase, ovulation, and the luteal phase, while the uterine cycle encompasses the menstrual, proliferative, and secretory phases.
Common Menstrual Disorders
Bleeding disorders that differ from the normal menstrual cycle bleeding pattern can be summarized under the term Abnormal Uterine Bleeding (AUB).
Dysmenorrhea (Menstrual Pain):
Primary Dysmenorrhea: This type of menstrual pain occurs without any underlying medical condition. Sometimes it is also described as idiopathic. It typically starts a day or two before menstruation and lasts for a few days into the period. The pain is often described as cramping and can range from mild to severe. It is caused by uterine contractions as the uterus sheds its lining.
Secondary Dysmenorrhea: This type of menstrual pain is associated with an underlying medical condition. Common causes include but are not limited to:
Endometriosis: A condition where tissue similar to the uterine lining grows outside the uterus, causing severe pain during menstruation.
Adenomyosis: A condition where tissue lining from the uterus (endometrium) grows into the muscular wall of the uterus, leading to increased menstrual cramping and heavy bleeding.
Uterine Fibroids: Non-cancerous tumors made from muscle tissue that grow inside the uterus that can cause pain and heavy bleeding during menstruation.
Amenorrhea (Absence of Menstruation):
Physiological Amenorrhea: This is a natural absence of menstruation that occurs during specific life stages such as childhood, pregnancy, or menopause.
Pathological Amenorrhea: This type of amenorrhea is not a normal part of the menstrual cycle and may be caused by various factors:
Primary Amenorrhea: When a girl has not experienced her first menstrual period by the age of 16, it may be due to anatomical issues or hormonal imbalances.
Secondary Amenorrhea: When a woman who previously had regular menstrual cycles stops menstruating for six months or more, it can be due to factors such as stress, excessive exercise, eating disorders, polycystic ovary syndrome (PCOS), or other medical conditions.
Altered Menstruation:
Women sometimes complain about variations in menstrual cycle frequency, flow, and timing. These conditions deviating from a typical menstrual pattern, may often point to potential health concerns within the female reproductive system.
These include:
Polymenorrhagia: This refers to unusually frequent menstrual periods, with cycles shorter than 21 days.
Oligomenorrhea: Oligomenorrhea is characterized by infrequent menstruation, where menstrual cycles are longer than 35 days.
Hypermenorrhea: This term is used when a woman experiences abnormally heavy menstrual bleeding.
Menorrhagia: Menorrhagia refers to prolonged and/or excessively heavy menstrual periods, often accompanied by clots. It can be caused by hormonal imbalances, uterine fibroids, or other underlying conditions.
Hypomenorrhea: Hypomenorrhea is the opposite of menorrhagia, where menstruation is very light or scant.
Metrorrhagia: This term describes irregular bleeding between menstrual periods.
Menometrorrhagia: This condition involves heavy and irregular bleeding, often a combination of menorrhagia and metrorrhagia.
Altered menstruation patterns can have various underlying causes, including hormonal imbalances, structural abnormalities in the reproductive organs, certain medications, or medical conditions.
Premenstrual Syndrome & Premenstrual Dysphoric Disorder
PMS and PMDD affect up to 75% of all menstruating women in their days leading up to the period. Emotional as well as physical symptoms e.g., breast tenderness, bloating, or irritability are only a few of the potential symptoms. If you want to read more about these conditions, visit our previous blog posts HERE.
Diagnostic Approaches for Menstrual Disorders
If menstrual irregularities persist, diagnostic evaluation is essential. Key steps include:
Medical history: This includes questions about genetic conditions, eating disorders, and stress levels. Understanding the patient's menstrual history and patterns is crucial. One very important aspect includes keeping track of one’s menstrual pattern for instance with an app-based period tracker or a period diary. It's essential to also inquire about any existing desire to have children, which should be considered during the assessments.
Physical Examination: A thorough physical examination may reveal signs such as hirsutism (excessive hair growth), which can indicate conditions like PCOS or high production of testosterone. Vaginal ultrasound may be used to find signs of fibroids or endometriosis.
Diagnostic Tests: Hormonal assessments play a vital role in identifying the underlying causes of menstrual disorders. These tests may include measuring hormones like HCG (human chorionic gonadotropin), estradiol, progesterone, LH (luteinizing hormone), FSH (follicle-stimulating hormone), and prolactin. These tests help differentiate between different types of amenorrhea as mentioned above, identify hormonal imbalances, and rule out conditions like hyperprolactinemia.
Approaches to Management and Treatment
Treatment for menstrual disorders depends on the specific condition and its underlying cause.
Here are some general treatment options:
Pain Management for Dysmenorrhea:
Nonsteroidal anti-inflammatory drugs (NSAIDs) such as Ibuprofen or Naproxen inhibit inflammatory pathways, lowering pain. Oral contraceptives are also often used to alleviate pain by regulating the menstrual cycle. In severe cases, surgical intervention may be necessary.
Addressing Amenorrhea:
Treatment varies depending on the type of amenorrhea. For primary amenorrhea, due to genetic disorders or anatomical abnormalities, interventions like hormone replacement therapy or surgery may be necessary. Secondary amenorrhea requires identifying and addressing the underlying cause, such as polycystic ovary syndrome (PCOS) or significant stress.
Managing Altered Menstruation:
The management of irregular bleeding patterns involves addressing the underlying condition. For example, treating uterine fibroids or endometriosis by minimally invasive surgery may alleviate symptoms. Hormonal contraception can also help regulate menstruation.
Premenstrual Syndrome (PMS) and Premenstrual Dysphoric Disorder (PMDD):
Lifestyle modifications, including stress reduction, dietary changes, and exercise, can help manage PMS. For PMDD, medications like selective serotonin reuptake inhibitors (SSRIs) or hormonal contraceptives may be prescribed. For further information about these conditions, have a look HERE.
Conclusion
Understanding the menstrual cycle and its disorders is crucial for promoting women's health and closing the gender data gap in medicine. By recognizing the complexity of this natural process and the various factors that can disrupt it, we can provide better healthcare and support to individuals experiencing menstrual irregularities. Whether it's dysmenorrhea, amenorrhea, altered menstruation, PMS, or PMDD, early diagnosis and appropriate treatment can significantly improve the quality of life for those affected. If you or someone you know is experiencing menstrual irregularities, consult your gynaecologist for a proper evaluation and tailored management plan.
References & Further Reading:
Heavy menstrual bleeding - Symptoms and causes - Mayo Clinic
Uhl: Gynäkologie und Geburtshilfe compact. Georg Thieme Verlag 2018, ISBN: 978-3-131-07346-4.
Findeklee, S. (2023). Der Menstruationszyklus. In: Endlich schwanger. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-662-66540-4_3
https://www.rosenfluh.ch/media/arsmedici-dossier/2013/12/Pramenopausale_Blutungsstorungen.pdf
This blog post was written by Dr. med. univ. Martin Kiebler, who is a gynaecologist working in one of Switzerland's largest women's clinics.
CLICK HERE to read more articles wrote by him.