Implantation bleeding: types, purpose and signs.


Implantation bleeding occurs when a fertilized egg attaches itself to the lining of the uterus (endometrium). Implantation usually takes place 6 to 12 days after fertilization and can cause light spotting or light bleeding, although this is not always the case.

About 15% to 25% of pregnant women will experience bleeding in the first trimester. Implant bleeding is a normal symptom and does not require medical attention. However, there are important signs to watch out for in case something more serious happens.

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You may see bleeding for a variety of reasons, even at the beginning of your period. You could even assume that implantation bleeding is the start of menstruation, since the timing is the same for both.

Many signs of implantation are similar to your menstrual cycle, so it can be difficult to tell if you are pregnant unless you have missed your period.

Three types of bleeding associated with your cycle and / or pregnancy:

  • Implantation bleeding: when a fertilized egg attaches itself to the lining of the uterus (endometrium).
  • Ovulation Bleeding: Light or spotting bleeding that occurs when an egg is released from the ovary.
  • Intermittent bleeding: If a fertilized egg does not implant in the wall of the uterus after ovulation, the mucous membrane will fall off.
Bleeding time
Bleeding implant 20 to 24 days
Ovulation bleeding 14 days
Bleeding period 28 days
* Based on a 28 day cycle

Early miscarriage can also cause bleeding and occurs in about 10% of known pregnancies.

Unlike other causes of bleeding, early miscarriage usually causes stronger, darker blood flow and spasms with visible tissue and blood clots passing through the vagina.

Pain and bleeding during a miscarriage may be worse than during your period. An early miscarriage can occur five weeks after ovulation.

Symptoms of miscarriage

The two main symptoms of a miscarriage are:

  • Vaginal bleeding
  • Abdominal cramps

If you feel pain or cramps with or without bleeding and you think you are pregnant, seek emergency help.

Bleeding can also occur during an ectopic pregnancy when a fertilized egg is implanted outside the uterus.

Ectopic pregnancy symptoms

Symptoms of an ectopic pregnancy include:

  • Bleeding
  • Spasms on one side of the body, mild to severe.

Call an ambulance if you suspect an ectopic pregnancy or feel pain.

Erosion of the cervix, also called eversion of the cervix , can also cause light bleeding or spotting. The cervix has an increased blood supply during pregnancy and can sometimes bleed, which is generally harmless.

This bleeding can occur as a result of irritation of the cervix during a pelvic exam. This sometimes happens after sex, so you should talk to your doctor.

Inversion of the cervix can also occur if you are not pregnant. This is a condition in which the cervical canal turns outward, exposing the cells inside the cervix to the acidic environment of the vaginal canal, causing it to become red, soggy, and potentially bleeding.

Inversion of the cervix is a normal physical abnormality that humans are born with. It can be caused by hormonal changes, making it more likely during adolescence, pregnancy, or while taking estrogen-containing contraceptives, such as pills.

Several other causes of non-pregnancy related bleeding include:

  • Fertility treatments such as IUI or IVF.
  • Intercourse
  • Endometriosis
  • Starting, stopping, or skipping doses of hormonal contraceptives
  • Side effects of fertility drugs
  • Thyroid gland diseases.
  • Polycystic ovary syndrome (PCOS)
  • Fibroids or polyps
  • Infections
  • Ovulation
  • Menstruation
  • Cervical Ectropion


When an egg is released from the ovary, usually once a month, ovulation occurs. At this time, the egg moves along the fallopian tube.

If sperm enter the egg and become fertilized as a result of sexual intercourse, they begin to divide into several cells, which move along the fallopian tube to the uterus.

It takes a few days for a fertilized egg to travel down the fallopian tubes before it is implanted by the body or discarded in the event of a failed implantation. If implanted, the hormone human chorionic gonadotropin (hCG) is produced in the uterus, which prevents the lining of the uterus from passing out.

If implantation does not occur, the egg and the lining of the uterus shed during the menstrual cycle.

After dividing into about 100 cells, the egg becomes a so-called blastocyst. There are many blood vessels in the lining of the uterus, so bleeding can occur when a fertilized egg (blastocyst) enters the lining of the uterus. This blood will flow through the cervix as with menstruation.


Implant bleeding is one of the first signs of pregnancy and occurs around the same time you are expecting your period. Since these two causes of bleeding can be confused, the best way to know for sure if you are pregnant is to take a pregnancy test.

It is important to note that many people may not experience any bleeding in early pregnancy.

If you are pregnant, your body will increase the production of human chorionic gonadotropin (hCG), which a test can detect.

However, there are differences between menstrual flow and implantation bleeding.

Some signs of implantation bleeding:

  • Light pink to rusty patches, light bleeding, or pink discharge
  • It can come and go or remain constant
  • It can last for hours or days.
  • Mild cramps
  • Headache
  • Nausea
  • Back pain
  • Change of humor
  • Tender breasts


Implant bleeding is normal and is not a risk factor. If the bleeding occurs more than a few days after the expected start of your period, it is most likely bleeding due to implantation.

If the bleeding is heavy, persistent, or lasts for several days, it is almost certainly not due to implantation and should be seen immediately by a doctor.

When to contact a healthcare provider

See your doctor for unexpected or irregular vaginal bleeding.

Get the word of drug information

Bleeding for suspected pregnancy can be alarming, but implantation bleeding is a common and normal sign of early pregnancy.

It can be difficult to know if the bleeding is due to implantation, your period, or another reason. Be sure to report any bleeding to your doctor if you think you are pregnant and seek emergency help if you experience abnormal heavy bleeding or pain if you know you are pregnant.

Frequently asked questions

  • Implantation, when a fertilized egg attaches itself to the lining of the uterus, usually occurs 6 to 12 days after conception.

  • In a typical 28-day cycle, implantation bleeding can occur between 20 and 24 days. Implant bleeding is usually light pink to rusty in color, with spots or light bleeding. This is usually accompanied by mild cramps and possibly headache, nausea, low back pain, mood swings, and breast tenderness.

    Menstrual blood tends to be thicker, darker in color, and last longer than implantation bleeding.

  • Implantation bleeding can last from several hours to a day or two. It is usually very light and can be permanent or go on and off for several days.

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