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What is bleeding during pregnancy and what are the causes


pregnancy, childbirth, children

diseases conditions and symptoms

Bleeding, which is observed in early pregnancy, is not a real menstruation, although it can occur around the moment when it is expected. That might make you not realize you are pregnant.

Author: Rositsa Tashkova, Master of Molecular Biology and Microbiology

Approximately 20% of pregnant women have some form of bleeding in the first trimester of pregnancy. Often this is not a cause for concern, but examination by a doctor is mandatory to establish the specific cause and take timely and adequate measures if necessary. [ref. 1]

If bleeding occurs in the second and third trimesters, immediately seek medical help without any delay.

Menstruation during pregnancy - myth or reality

In the not-too-distant past, women have not had access to so much information, and cases of so-called "black lives" have not been accessed. "colored pregnancy", in which the woman realizes that she is months pregnant after conception, were not such ararity.

The bleeding that occurs in a colourful pregnancy is not a real menstruation - although it may occur around the time it is expected. This may mislead the woman that she is not pregnant until the fourthmonth.

The phenomenon is due to the dropping of parts of the mucous membrane of the uterus (endometrium), which is not yet covered by the growing fruit bag of the embiroxon. After the 16th gestational week, the fruit sac has completely taken over the surface of the mucous membrane, and the bleeding stops. [ref. 2]

It can be established that the woman is pregnant if she doubts that something is wrong and visits her gynecologist. The condition is not dangerous.

Hormonal changes as a cause of bleeding at the beginning of pregnancy

Another reason for such bleeding is hormonal changes. In this case, some women have a slight bleeding about 4 to 8 weeks of pregnancy or around the time their menstruation should occur. This can be very confusing and is why these women do not realize that they are pregnantfor a while.

In this case, usually bleeding stops around week 13, since at this point the placenta is developed enough to produce all the hormones needed to maintain pregnancy. In particular, progesterone, whose deficiency makes the lining of the uterus unstable.

Embryo implantation can also cause mild bleeding or spotting

Another possible explanation for the bleeding, which can fool us that it is the onset of menstruation in a very earlypregnancy, is implantation bleeding , which looks more like spotting and can occur around the moment of the first late menstruation.

However, implantation bleeding occurs only once - in the first month of pregnancy. It is due to the destruction of small blood vessels in the process of implantation or "nesting" of the fertilized egg in the uterine mucosa. It lasts only a day or two, it is quite light and has a pink or brown color. [ref. 3]

Besides implantation bleeding, after the egg is implanted in the endometrium, sometimes this leads to slight bleeding, which on early examination turns out to be a small hematoma (blood collection). This is not something to worry about. The hematoma will gradually disappear, and in most cases the pregnancy is preserved without complications.

Polyp or erosion of the cervix

In some women, polyps of the cervix are formed - the area that connects the uterus to the vagina. Under the influence of increased hormonal levels during pregnancy, the polyp can grow. Its surface is easily wound and can bleed during sexual contact or even only with physical exertion on the part of the mother. Polyps are not usually treated during pregnancy.

Erosion of the cervix (also known as cervical ectropion) can be a cause of spotting or bleeding. Blood supply to the uterus and its cervix increases during pregnancy, and the cervix can bleed painlessly without causing problems. Erosion can also cause bleeding after intercourse, and this type of bleeding should also always be reported to the obstetrician-gynecologist. [ref. 4]


Besides harmless causes of bleeding, which do not require treatment, but only observation, there are several worryingreasons , for which bleeding can also be observed in the firsttrimester.

Such a cause are infections with certain microorganisms, such as chlamydia, trichomones, herpes, gonorrhea. They should be treated , as they can cause miscarriage and other complications of pregnancy. Treatment is mandatory under the supervision andon the prescription of the attending obstetrician-gynecologist.

Molar pregnancy

Molar pregnancy is a type of gestational trophoblast neoplasm. This is a very rare disease in which severely elevated levels of the pregnancy hormone HMG, abnormally rapid growth of the abdomen, bleeding, severe vomiting are observed.

In molar pregnancy, abnormal tissue develops instead of a baby. In rarecases, this tissue can be cancerous and metastasize. [ref. 5]

It is believed that sometimes it is likely that molar pregnancy is due to an egg without or an egg with an inactivated nucleus fertilized by spermatozoa, which has doubled its own chromosomes.

Molar pregnancy does not end with baby wear.

Ectopic pregnancy

In ectopic pregnancy, the fertilized embryo is implanted outside the uterus, usually in the fallopian tube.

If the embryo continues to grow, this can lead to a violation of the integrity of the fallopian tube, which can be life-threatening for the mother. Although ectopic pregnancy is potentially dangerous, it is observed only in about 2% of pregnant women. [ref. 6]

ectopic pregnancy, embryo
Embryo at 5 weeks (7 g.s.), from ectopic pregnancy. Credit: Ed Uthman, flickr

Other symptoms of ectopic pregnancy are severe cramps or some pain in the lower abdomen around the ovaries and dizziness. Bleeding is more of a brownish spotting.

In ectopic pregnancy, the home pregnancy test may be positive, but with a negative and doubt, a blood test and examination are carried out. Ectopic pregnancy is dangerous for the mother and therefore its interruption is necessary.

Miscarriage or "missed abortion"

Since miscarriage is most common in the first 12 weeks of pregnancy (until the 20th c.), it is one of the most serious causes of bleeding in the first trimester. However, bleeding during this period does not necessarily mean that we have lost the baby or will have anabortion.

Other symptoms of miscarriage are severe cramps in the lower abdomen and tissues leaking through the vagina.

The cause of miscarriage is not always known, but in some cases this occurs due to improper development of the embryo or a problem with the pregnancy itself. In 50% of miscarriages, the cause is chromosomal abnormalities in the fetus.

Of course, for most women, miscarriage is a very sad and disturbing experience and they need the strong support of partners and loved ones. Usually in her grief the woman blames herself, but in the vast majority of cases she is not at all at fault!

Symptoms of miscarriage are different. In some cases, there may be only a slight spotting, in others the bleeding may stop and more severe bleeding with clots and pains may occur again. Sometimes there may be no bleedingat all.

The so-called "mysed abortion" or interruption of the embryo's cardiac activity in the early stagesof pregnancy , often established during a routine examination at thegynecologist. [ref. 7]

In these cases, termination of pregnancy is necessary, since it has no chance of development . In case of early pregnancy loss, part of the tissue may remain in the uterus. This tissue must be removed. This can happen by allowing the tissue to pass naturally, or it can be removed with the help of medicationor surgery.

Whatever the cause of bleeding during any stage of pregnancy, consultation with a doctor and seeking medical attention are mandatory , in order to preserve the life and health of the mother and, if possible, the fetus. Bleeding should not be taken dramatically, especially before the causeis established. Let us think positively, but take the necessary measures to make the situation happy. :)

Read more:

6 initial symptoms of pregnancy

What should I do before I get pregnant

Diabetes during pregnancy: symptoms, risks and advice

Food for good children's mental development since conception

  1. Menstruation during pregnancy - myth or reality
  2. Hormonal changes as a cause of bleeding at the beginning of pregnancy
  3. Embryo implantation can also cause mild bleeding or spotting
  4. Polyp or erosion of the cervix
  5. Infections
  6. Molar pregnancy
  7. Ectopic pregnancy
  8. Miscarriage or "missed abortion"


  1. Bleeding During Pregnancy. American College of Obstetricians and Gynecologists. Updated February 2019.
  2. Potential Causes of Bleeding During Pregnancy. Medically reviewed by Brian Levine, MD, MS, FACOG.
  3. In English: 6 initial symptoms of pregnancy
  4. Bleeding and/or Pain In Early Pregnancy. Nhs
  5. Current management of molar pregnancy. Journal of reproductive medicine.2002
  6. Bleeding During Pregnancy. Webmd
  7. Missed abortion. Science Direct.

The author

👩 🔬 Rositsa Tashkova-Kacharova has a Bachelor degree in Molecular Biology and a Master's degree in Microbiology and Microbiological Control. She completed her Master's thesis at the University of Nantes, France. At that time she painted a Christmas tree of bacteria and inspired the announcement of the first competition for drawing with microorganisms Agar Art. For 3 years she was the editor of the journal Bulgarian Science and continues to write about science and medicine.
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