Is delayed menstruation caused by lack of blood in the body? Is it a distress signal from the body that menstruation is delayed by five days every month?

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A few days ago, "It turns out that delayed menstruation is caused by lack of blood in the body" became a hot search. Many people "popularize science": the body has a self-regulating mechanism. If it senses that "blood is not enough", it will delay menstruation; and when the blood is sufficient, menstruation will return to normal.

Image source: Weibo screenshot

How scientific is this statement? Is delayed menstruation really just due to lack of blood in the body?

Analysis of ischemia and anemia are not the same thing

The concepts of "ischemia" and "anemia" are easily confused, but in fact, they mean completely different things.

Ischemia in the medical field refers to the blood supply to certain organs, tissues, and muscle groups in the body being restricted due to vascular disease, trauma, infection, etc., which prevents cells from obtaining oxygen to maintain normal metabolism, ultimately leading to tissue damage or dysfunction.

Its symptoms are often visible to the naked eye. There are many similar news reports on the Internet: someone hasn't worn a ring for a long time, and when they put it on again, it got stuck on their finger and couldn't be taken off, resulting in swelling of the finger. This is actually ischemia.
When netizens mention the topic of menstruation, they mostly refer to "anemia" when they talk about lack of blood in the body.

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Anemia refers to a clinical symptom in which the hemoglobin concentration, red blood cell count and hematocrit per unit volume of blood are lower than normal values. Simply put, it means a decrease in the total number of red blood cells and hemoglobin in the blood.

Most of its symptoms can only be understood intuitively, such as dizziness, tinnitus, fatigue, and insomnia.

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According to the cause, there are three main types of anemia: hypoplastic anemia, excessive red blood cell destruction anemia, and hemorrhagic anemia. The most common type is iron deficiency anemia, which is caused by the lack of "iron nutrients" in the body.

However, usually, mild anemia does not have much impact on menstruation. Only severe anemia can cause delayed menstruation or less menstrual flow. For people with severe anemia, more obvious symptoms are dizziness, fatigue, pale skin, palpitations and shortness of breath.

In addition, what you think is "delayed menstruation" may not actually be delayed.

Delayed menstruation is not what you think

Let’s do a multiple-choice question first:

Netizen A said: Her period is delayed for a few days every month. Last month it was on the 5th, last month it was on the 10th, and this month it was delayed to the 15th.

Netizen B said: Her period usually comes on the 10th of every month, but this month it came on the 13th.

Which of the above situations is considered delayed menstruation? The answer is: none of them.

First of all, we need to make it clear that although menstruation contains the word "month", it does not strictly come in units of "30" days.

A woman's menstrual cycle usually includes three phases: the follicular phase, the ovulatory phase, and the luteal phase.

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The follicular phase refers to the period from "menstruation onset, follicles begin to develop" to "one of the follicles matures and is eventually discharged". During this process, under the influence of gonadotropin, the primordial follicles in the ovaries will continue to grow.

It is worth noting that the duration of the last two stages of the menstrual cycle - ovulation and luteal phase - is often unchanged, at one day and fourteen days respectively, while the speed of follicle development varies from person to person, which means that everyone's menstrual cycle will be different.

As long as the menstrual cycle is between 21 and 35 days, it is normal. There is no need to use the same specific dates as the basis for judging whether the menstruation is delayed.

For example, netizen A, her menstruation actually comes very regularly, with an interval of 35 days each time.

Secondly, menstruation is easily affected by factors such as mood, exercise, and diet, and it may occasionally be "late or early". If the menstrual cycle is relatively fixed, and it only comes early or late once in a while, and if the menstrual cycle is still between 21 and 35 days or the number of days late is within 7 days, there is no need to worry too much. If it exceeds 7 days, it is considered a real delay in menstruation.

What are the factors that lead to delayed menstruation?

In addition to anemia, there are actually many other factors that lead to delayed menstruation.

1. Pregnancy

"Pregnancy will cause no menstruation" is common knowledge, but few people know the principle behind it.

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As we mentioned earlier, the last stage of the menstrual cycle is the luteal phase, which means that when an egg in the ovary matures and is released, the follicle wall collapses and becomes a corpus luteum, which continuously releases estrogen and progesterone, further thickening the endometrium.

If the egg does not combine with the sperm within 14 days, the corpus luteum will shrink, causing the already thickened endometrium to lose support and peel off and bleed. However, if the egg combines with the sperm, the corpus luteum will become a corpus luteum of pregnancy, continue to secrete estrogen and progesterone, and continue to nourish the endometrium. Naturally, menstruation will not come.

Sisters who have sexual life, if your period is more than 7 days late, you can consider using a pregnancy test stick to check whether there are two lines.

2. Medication

Medications containing progestin, such as progesterone and emergency contraceptive pills, can also cause your period to be delayed.

The principle of this type of drug is actually to prolong the luteal phase, allowing progesterone to continue to support the endometrium, thereby delaying the arrival of menstruation.

3. Endocrine disorders

In the topic of weight loss, many people have shared similar experiences: after losing weight for half a month, menstruation stopped. In fact, this is because excessive weight loss can lead to malnutrition or too low body fat percentage, which affects the synthesis of estrogen.

Of course, being excessively obese is not a good thing either. Too much fat can cause endocrine disorders, thereby affecting the secretion of gonadotropin, causing the follicles to fail to develop and ovulate normally, thus causing menstrual abnormalities.

In addition, irregular sleep, day and night reversal, staying up late and other factors can also cause endocrine disorders and delay menstruation.

4. Surgery

Surgery often causes anxiety or excessive tension, which in turn affects the menstrual cycle.

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If ovarian-related surgery is performed, changes in ovarian hormones may also cause menstrual changes. In addition, intrauterine surgeries such as artificial abortion may cause adhesions of the uterine wall, leading to uterine cavity occlusion, delayed menstruation and reduced menstrual flow.

5. Chronic diseases

Chronic wasting diseases such as chronic hepatitis, tuberculosis, and tumors can lead to nutritional deficiencies in the human body, thereby causing menstrual changes.

6. Gynecological endocrine diseases

If you experience delayed menstruation and have symptoms such as obesity, hirsutism, and acne, you may have polycystic ovary syndrome. If you are under 40 years old and have not had your period for a long time, excluding factors such as pregnancy, it is best to go to the hospital for a detailed examination to see if you have premature ovarian failure.

Copyright stock images, no permission to reprint Conclusion

1. Ischemia refers to a pathological phenomenon of an organ or tissue, which is often not directly related to delayed menstruation. However, severe anemia in the human body may indeed lead to delayed menstruation.

2. Whether menstruation is delayed needs to be analyzed and judged individually based on each person's different menstrual cycle.

3. Anemia is not the only reason for delayed menstruation. If it is delayed for a long time and exceeds the normal range, it is best to go to the hospital for a check-up. Don’t just use the word "anemia" to get rid of it. It may cover up real problems in your body.

Menstruation is just the result of ovarian cyclical changes, but it is closely related to the health of the ovaries. For every woman, how to understand it represents how to understand our body.

References

[1]Carol N. Monis; Maggie Tetrokalashvili. (2019). "Menstrual Cycle Proliferative And Follicular Phase". Treasure Island (FL): StatPearls Publishing. PMID 31194386.

[2]Weschler, Toni (2002). Taking Charge of Your Fertility (Revised ed.). New York: HarperCollins. pp. 359–361. ISBN 0-06-093764-5.

[3]Reed, Beverly G.; Carr, Bruce R. (2000), Feingold, Kenneth R.; Anawalt, Bradley; Boyce, Alison; Chrousos, George (eds.), "The Normal Menstrual Cycle and the Control of Ovulation", Endotext, South Dartmouth (MA): MDText.com, Inc., PMID 25905282.

[4] Holesh, Julie E.; Bass, Autumn N.; Lord, Megan (2021), "Physiology, Ovulation", StatPearls, Treasure Island (FL): StatPearls Publishing, PMID 28723025.

[5] Zhang E, Li

This article is a work of Science Popularization China-Starry Sky Project

Produced by: Science Popularization Department of China Association for Science and Technology

Producer｜China Science and Technology Press Co., Ltd., Beijing Zhongke Xinghe Culture Media Co., Ltd.

Planning｜Fu Sijia

Author｜Li Mi Popular Science Creator

Review | Lan Yibing, deputy chief physician, Department of Obstetrics and Gynecology, Zhejiang University School of Medicine