Implantation bleeding – at what time does it occur?
Approximately 5 to 6 days after fertilization of the egg, the embryo implants in the lining of the uterus. At this stage of embryonic development, one speaks of the so-called blastocyst. This blastocyst releases enzymes, also known as proteolytic enzymes.
They decompose proteins and thus tissue and thus enable the embryo to implant. During this process, small blood vessels in the well-built endometrium can be damaged. This results in a slight bleeding, also known as implantation or nidation bleeding.
Whether or not implantation bleeding occurs depends on the individual woman and is therefore not a sure sign of pregnancy. The occurrence of an implantation bleeding is also not to be considered a good or bad sign, but simply corresponds to an individuality in the development of a pregnancy. Women who have had an implantation bleeding in a previous pregnancy do not have to have one again in future pregnancies.
Causes for implantation bleeding
The implantation bleeding is also called nidation bleeding in medical terminology. The implantation of the so-called blastocyst, which is an early stage in embryonic development, does not occur on the first day of fertilization, but on the 5th day after fertilization. The blastocyst is then developed to the point where it can implant itself in the lining of the uterus.
This implantation usually occurs on the back wall of the uterus, but it is also possible on the front wall. The implantation takes place through the release of enzymes that can dissolve proteins – and thus tissue – in the lining of the uterus. This enables the blastocyst to attach itself to the mucous membrane.
This can lead to a slight bleeding, which drains vaginally and is therefore noticed by some women. However, implantation bleeding does not occur in every woman, so it is not a sure sign of pregnancy. However, it can be an indication of a developing pregnancy.
