Introduction:
Melatonin is a hormone produced in females by a pineal gland. This hormone plays a major role in the human menstrual cycle. A normal menstrual cycle gives an insight into the overall health and hormone balance in the body. Melatonin hormone helps in the regulation of the menstrual cycle by about when to start and the length of the cycle. Melatonin production may be affected with aging and as females reach menopause.
What Is Melatonin?
Melatonin is a hormone produced in the brain by the pineal gland. In response to darkness, it is secreted and helps in maintaining sleep and circadian rhythms (24-hour internal clock). At night time, getting exposed to light may stop the secretion of melatonin. In the human body, it also plays in other functions of the body other than sleep.
Melatonin is made of tryptophan and produced from serotonin, through a link of enzymatic reactions. It is produced by many tissues of the body, but the main source is the brain. At night, the reduced light entering the eye sends a signal via the optic nerve to the pineal gland. It is secreted into the blood and cerebrospinal fluid (fluid around the brain and spinal cord) and gives signals to other organs of the body. Tissues that contain receptors for melatonin can detect the peak levels of melatonin hormone at night. Daytime concentration is less when compared to night (tenfold higher).
The melatonin hormone regulates reproduction, behavior, and growth of the human body as a response to the length of the day. In puberty, melatonin levels decrease at night. This shows that melatonin may have a role in reproductive development. Melatonin secretion increase to peak level at one to three years of age, then decline, and a constant level is reached and persists throughout early adulthood. As humans age, there is a decrease in levels of melatonin.
What Happens When There Is a Variation in the Levels of Melatonin?
Variations in levels of melatonin do not affect health, but increased melatonin in the body shows drowsiness and decreased core body temperature. Very large doses have effects on the reproductive system and also have antioxidant action.
What Is an Irregular Menstrual Cycle?
Menstruation is normal vaginal bleeding in females as a monthly cycle. The time span between the first day of one period to the first day of the next period is called a cycle. It is around 22 to 35 days. If any variation is observed for a long time, it is always better to get help from a healthcare professional to get the body back in balance. A disturbed menstrual cycle may cause changes in mood, body image, infertility, affected quality of life, and pregnancy complications.
There are many reasons for irregular menstrual cycles such as stress, disturbance in sleep, certain medications, medical conditions like fibroids, cervical or uterine polyps, and chromosomal abnormality. Exercise and balanced diet help regulate the menstrual cycle.
How Does Melatonin Play a Role in the Menstrual Cycle?
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When the body is overloaded with stress, it produces more stress hormones leading to an overall hormonal imbalance. In case of decreased sleep, melatonin as well as stress hormones are affected leading to irregularity in the menstrual cycle. Melatonin regulates the menstrual cycle and hence gets affected.
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Melatonin affects the secretion of follicle-stimulating hormone (FSH), luteinizing hormone (LH), and oxytocin levels. FSH helps stimulate the growth of follicles in the ovary, and LH manages the regulation of the menstrual cycle. Hence when there is an imbalance in the melatonin it affects FSH and LH leading to an irregular menstrual cycle.
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The female reproductive system is regulated by the hypothalamic-pituitary-gonadal (HPG) axis. In the early stage of the menstrual cycle, when there is a rise in FSH occurs it stimulates estrogen secretion and later stimulates LH. Release of oocyte occurs after 36 to 40 hours of LH surge at midcycle. After this, all hormones return to the same basal levels. \
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Eating and sleeping disorders lead to an irregular menstrual cycle which is an indication of multiple reproductive diseases.
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Circadian rhythm and environment cycles should be balanced for the fitness of the human body. Imbalance of these two leads to diseases.
What Happens When Circadian Rhythm Imbalance Occurs?
Circadian rhythm imbalance leads to the following conditions:
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Poly Cystic Ovarian Syndrome: A study showed that disruption in sleep-wake behavior is also associated with insulin resistance in polycystic ovarian syndrome (PCOS).
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Premature Ovarian Insufficiency (POI): A disease which shows insufficient ovarian activity among lesser than 40 years of age group with high gonadotropins and low estrogen. Studies have shown that there is a relationship between circadian rhythm and the environmental cycle. Some of the genes are affected at the HPG axis which is also responsible for these changes.
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Premenstrual Syndrome (PMS): A mood disorder occurring due to sleep disorder.
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Dysmenorrhea: Menstrual cramps or pain before or during menstruation.
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Central Precocious Puberty: Puberty starts at an early age (around 8 years).
What Is the Treatment of Irregular Menstrual Cycle Caused Due to Melatonin Imbalance?
By adapting to the original circadian rhythm, treatment can be planned. Treatment methods include:
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Light Exposure Modulation: Light therapy relieves anxiety in PMS and PCOS.
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Behavioral Modulation: Includes lifestyle modification like having good nutrition, and regular exercises to help in reducing body weight and thereby improvement in PCOS conditions.
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Pharmacological Interventions: Melatonin supplementation or receptor agonists are useful in such cases along with lifestyle modifications.
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Circadian molecule drugs are under trial for treating many diseases which enhance the activity of transcription factors at the gene level.
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Chronotherapy: Recent advancement referring to timed dosing of drugs to increase treatment efficacy and patient tolerance. However, it is still unknown in the treatment of the reproductive system of females as further research is needed.
Conclusion:
The normal routine which was followed in the olden days has been replaced by modern technology and changes in working patterns. These changes along with changes in lifestyle, eating, and sleeping habits have led to many modern diseases. To combat these, it is necessary to know the circadian system and detailed knowledge about changes going on in human bodies to manage them successfully.
