Which is healthier, dark menstrual color or light menstrual color?

The saying "different menstrual colors represent different diseases" has been circulating on the Internet for a long time. Many women can't help but identify themselves when changing sanitary napkins... and judge their physical condition by the color of menstrual blood.

Image source: A social platform

If you observe carefully, you will find that even in the same menstrual cycle, the color of menstruation may be different. The day before yesterday, it may be pink, and today it has turned into dark red. Since it is all blood, why is the color not fixed? Is there really something wrong with the body?

Don't worry, most people don't realize that during menstrual bleeding, there is more than just "blood" discharged from the body. What you think is "abnormal color" may just be the fault of menstrual blood.

The composition of menstrual blood is not simple

We have already mentioned before that menstruation is the result of the periodic thickening and shedding of the endometrium. (Click here to learn more → Which is normal, 3 days or 7 days for menstruation?)

Therefore, if you want to understand the composition of menstrual blood, you need to understand what the endometrium is.

The female uterus is distributed with endometrium, myometrium and uterine serosa from inside to outside, and the endometrium is divided into two layers: basal layer and functional layer.

In simple terms, the basal layer is fixed and does not change. It prevents adhesions in the uterine cavity and keeps the uterine cavity open. It is the functional layer in the endometrium that is affected by ovarian hormones.

Out of physiological instinct, the ovaries will breed more than a dozen primordial follicles every month, and select the best ones to develop into eggs and release them. During this period, the ovaries also need to continuously secrete estrogen and progesterone to nourish the functional layer of the endometrium, making it a fertile soil for the fertilized egg.

After ovulation, the follicle will form a corpus luteum, which is the main source of progesterone. If the egg does not combine with the sperm, the corpus luteum will slowly shrink, progesterone will decrease, and the endometrium will lose the support of progesterone, the functional layer of the endometrium will shrink and fall off, and bleeding will form menstruation.

At this point, the composition of menstrual blood is also obvious. It includes three-quarters of arterial blood, one-quarter of venous blood, and some fine fleshy tissues of the functional layer of the endometrium. But what women observe on sanitary napkins is actually more than just menstrual blood.

The shed functional layer of the endometrium will be discharged from the uterus through the cervix and into the vagina, carrying some other substances along the way. For example, in order to protect the vagina and prevent dirt from entering, a kind of adhesive secreted by the cervix and vagina is called leucorrhea.

Normally, leucorrhea is a white, yellow, transparent, sticky liquid, a bit like egg white. So, every time you think the color of your menstrual blood changes, it may actually be affected by the mixture of leucorrhea.

Menstrual color, more than one

Although we already know that menstrual blood is always mixed with other substances during menstruation and its specific color cannot be distinguished by the naked eye, we can still judge whether there is something wrong with the body by the color of the sanitary napkin.

1. Pink

If you observe that your menstrual blood is pink, don't rush to suspect that your blood concentration has decreased.

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In fact, the endometrium does not shed all at once, but sheds every day during the bleeding period. Therefore, the menstrual bleeding period often lasts for 3 to 7 days and can come in multiple times.

Normally, when menstruation just comes, the functional layer of the endometrium has just shed, and the amount of menstrual blood is relatively small. At this time, the bright red blood will mix with vaginal secretions, causing the color to become lighter and appear pink.

2. Bright red

Bright red means that the menstrual period has reached its peak, the shedding of the endometrium has increased, and the uterus will continue to contract at this time, so the amount of menstrual blood discharged will also increase.

At this time, menstrual blood accounts for the majority of the substances absorbed by the sanitary napkin, so what you observe will be the most common color, which is the color of blood.

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3. Dark red

Menstrual blood is discharged from the uterus through the cervix and out of the vagina, but it cannot always be discharged in time.

If the menstrual flow is relatively small and does not flow out actively, it will accumulate in the uterine cavity or vagina due to its slow flow rate. When the iron ions in the blood are oxidized, the blood will turn dark red.

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4. Brownish red

In movies and TV shows, black blood usually means poisoning. However, if menstrual blood is discharged after a long time and has been deeply oxidized, it will also appear this color.

When the menstrual period is about to end, the dark blood will mix with the vaginal discharge. Think of the color palette you played with as a child. When black, red, white and yellow are added together, brown will naturally appear.

What color of menstrual blood should be a cause for concern?

As we said just now, what affects the color of menstruation is not only the menstrual blood, but also the vaginal secretions and other substances that mix with it every time. If the following colors appear, you should be vigilant.

1. Orange

Orange menstrual blood may be the result of an infection. Think about the color matching principle we learned before. How did orange come about? The answer is: red and yellow.

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If you are infected with bacterial vaginosis or a sexually transmitted infection caused by parasites, your vaginal discharge may appear yellow-gray or yellow-green, which will change the color of your menstrual period.

A sexually transmitted infection caused by a parasite, also known as Trichomonas vaginitis, which lives in the vagina of women and the foreskin folds, urethra, and prostate of men. It is often spread through sex and in public baths, toilets, clothing, etc.

Most men who are infected with Trichomonas have no symptoms, so they can easily become a source of infection. Therefore, if you find that your menstrual discharge is orange and you have symptoms of genital itching, burning, and lower abdominal discomfort, it is best not to minimize the problem and believe that it is simply vaginitis, but to seek medical attention in time. It is best to take your male partner with you for a check-up, just in case.

2. Gray/Green

These two colors, which are far away from red, are also reminding you that you may be infected.

Both bacterial vaginosis and gonococcal vaginitis can change the color of leucorrhea, and when it mixes with menstrual blood, it will make the color of menstrual blood become strange.

One thing you should pay special attention to is to always pay attention to your menstrual cycle and the duration and flow of bleeding.

If one day, you suddenly bleed long outside your normal menstrual cycle, you must be alert to whether it is early menstruation or abnormal bleeding caused by symptoms such as uterine fibroids.

References

[1]Aguilar,HN;Mitchell,S.;Knoll,AH;Yuan,X.(2010)."Physiologicalpathwaysandmolecularmechanismsregulatinguterinecontractility".HumanReproductionUpdate.16(6):725–744.

[2] Gargett, CE; Schwab, KE; Zillwood, RM; Nguyen, HP; Wu, D. (June2009). "Isolation and culture of epithelial progenitors and mesenchymalstem cells from human endometrium". Biology of Reproduction. 80(6): 1136–1145.

[3] Emera, D; Romero, R; Wagner, G (January2012). "Theevolution of menstruation: a new model for genetic assimilation: explaining molecular origins of maternal responses of etal invasiveness". BioEssays. 34 (1): 26-35.

[4]Hormonaleffectsinnewbornsretrievefromhttps://medlineplus.gov/ency/article/001911.htm

[5]Menstruationandthemenstrualcyclefactsheetretrievefromhttps://web.archive.org/web/20150626134338/http://www.womenshealth.gov/publications/our-publications/fact-sheet/menstruation.html

Author: Wu Zhaodi, popular science writer

Review丨Xia Lihua, Deputy Director and Chief Physician, Department of Gynecology, Zhejiang Provincial People's Hospital