What is an implantation bleed?
After fertilization, the fertilized egg (blastocyst) migrates through the fallopian tube towards the uterus and nests – like an egg in a nest (lat. nidus, nest) – in the lining of the uterus. This nesting is called nidation by physicians.
What begins with the attachment of the blastocyst to the mucosa ends with the penetration of the fertilized egg into the outer layer of the uterine wall, where it is enclosed by new epithelium. The word implantation is often used in this context. During the migration of the blastocyst into the uterine wall, small blood vessels are sometimes damaged, which may result in slight bleeding. Gynecologists refer to this as nidation bleeding (implantation bleeding, implantation bleeding).
When does implantation bleeding occur?
The first attachment of the fertilized egg begins about five to six days after fertilization. About twelve days after fertilization, the process of nidation (implantation) is complete. Towards the end of this process, i.e. between about the seventh and twelfth day after fertilization, implantation bleeding occurs.
How strong is the implantation bleeding?
How long does a nidation bleed last?
Since only small vessels are injured during implantation, nidation bleeding subsides quickly. It usually lasts only about one to two days. In rare cases, it may last a little longer. If you are unsure, you can ask a doctor for advice in this case. Describe the bleeding to him or her in more detail (type and extent of bleeding? Since when?).
Implantation bleeding or menstrual bleeding?
Some women report that they have already been pregnant despite having their period. However, this is not possible. In these cases, women often confuse implantation bleeding with their menstrual bleeding. Some pregnant women also mistakenly report the time of nidation bleeding as their last period, which can lead to an incorrect calculation of the due date. However, there are some characteristics that can help you distinguish between the two bleeds.
- Timing: menstruation begins about 14 days after ovulation. If bleeding occurs earlier in the cycle, it is probably implantation bleeding.
- Color of blood: Light reddish blood indicates implantation bleeding, while brown to dark red blood indicates menstruation.
- Strength: Period bleeding is usually relatively heavy and increases in intensity as it progresses. Implantation bleeding is comparatively light and does not become heavier.
- Pain: Typical period pains such as cramps in the lower abdomen are rather rare in nidation bleeding; it is usually painless.
Pay attention to other complaints as well: Tiredness, tightness of the breasts or nausea can also herald pregnancy.
What to do in case of nidation bleeding?
Nidation bleeding is not dangerous for the woman or for the further course of the pregnancy. If the signs point to implantation bleeding, a pregnancy test or an examination by a gynecologist can give you clarity as to whether you are actually expecting a child.
