What Is Implantation Bleed?

Implantation bleeding is a slight loss of blood that occurs in early pregnancy. That doesn’t happen to all women. It appears around the time menstruation is supposed to start and is therefore a source of confusion for many mothers.

One of the most obvious symptoms of pregnancy is a missed period. However,  in some women, this absence is interrupted by implantation bleeding,  which, as the name implies, involves bleeding but not menstrual bleeding.

Implantation bleeding is also known as nidation. For those who already have signs that they are pregnant, it can arouse the suspicion of a miscarriage. To avoid confusion, it is best to be well informed so as not to leave room for misunderstandings.

Bleeding from implantation

Implantation bleeding is a normal phenomenon in a healthy pregnancy. It occurs between 6 and 12 days after fertilization of the egg, on a date that coincides, to a greater or lesser degree, with the usual menstruation.

It is usually accompanied by cramps less intense than menstruation. Headache, nausea, mood swings, breast tenderness, lower back pain, abdominal swelling and fatigue are also common.

Implantation bleeding does not usually follow a fixed pattern. A woman who has had children may experience this type of bleeding in some pregnancies and not others. Sometimes it’s just a drop of blood and other times it’s like a light period.

from egg to embryo

When fertilization occurs,  the union between the egg and sperm gives rise to the zygote, which is the fertilized egg. In just 72 hours, the zygote transforms into morula, which is a segmented zygote. Four to five days later, the morula turns into a blastocyst.

The blastocyst, or blastula, has one set of outer cells and another set of inner cells. The former will become the protective membrane and the latter the embryo. Only when this blastocyst is implanted in the uterus can one speak of an embryo .

About a week after fertilization, the blastocyst begins to make prolongations. They are what allow it to attach itself to the lining of the uterus. At this early stage, the uterus is highly irrigated and bleeds easily. Therefore, implantation can cause bleeding.

Differences between implantation bleeding and menstrual bleeding

This type of bleeding is very mild, and is usually only detected by a small stain  on your underwear or toilet paper.  It is rarely anything more bulky. It has a color that can be dark pink or brown, but not red. It has no clots and lasts between a few hours and three days.

In implantation bleeding, there is no gradual increase in flow, as occurs in menstruation. It has an intermittent frequency but remains as a light spot that does not increase.

If pregnancy is suspected and bleeding is more intense in color, or if it suddenly flares up, it is best to see a doctor. In some cases this is a symptom of miscarriage, or it could be a sign of ectopic or molar pregnancy. It could also indicate that there is a health problem.

Confirmation of pregnancy

In the early stages, it is very difficult to establish whether there is a pregnancy or not. For the same reason, it is not easy to determine if what is happening is implantation bleed, threatened miscarriage, or other problem. Hence the importance of confirming the pregnancy as soon as possible.

The most reliable pregnancy tests can be done during the first week of pregnancy. These are tests carried out in the laboratory with a high degree of success. In contrast, home tests have a lower degree of reliability when performed soon after fertilization.

All of these tests measure the level of the hormone human chorionic gonadotropin (HCG), which is present in the blood and urine. Home tests can be done during implantation bleeding, but it is best to wait a week for more reliable results.