After successfully crossing the fallopian tube, the fertilized egg enters the uterine cavity. There it needs to attach (infiltrate, implant) into the endometrium. To do this, the embryo begins to actively produce special enzymes that can destroy endometrial cells. Under the action of these enzymes, a small depression is created in the endometrium, into which the embryo is settled (implanted). This process lasts no more than 40 hours.
Important: in the process of creating a depression, damage to a small number of small blood vessels is possible. Women at this moment may notice a small amount of bloody discharge. In terms of timing, this is the 22-23rd day of the menstrual cycle, that is, a week before the next menstruation.
It may turn out that the embryo will attach to that part of the endometrium where there are few blood vessels. Then there will be no implantation bleeding, and the woman will not even notice that implantation has occurred.
It happens that a woman’s menstrual cycle is shortened. With this scenario, implantation of the fertilized egg may occur at the moment when the next menstruation is expected. This is often what is mistaken for implantation bleeding.
In order not to miss anything important in your health, you need to know the following points:
• implantation bleeding is never intense (usually one daily or thin pad is enough);
• it never gets stronger;
• such bleeding is never accompanied by pain and/or deterioration in general health;
• implantation bleeding stops no later than 40 hours from the moment it begins.
If at least one of these points is not true, then you must definitely see a gynecologist and find the cause of the bleeding.
Could anything interfere with successful implantation? Unfortunately yes. Abnormalities in the structure of the uterus, scars after operations, chronic inflammation and hormonal disorders, leading to thinning of the endometrium. All this can lead to the fact that the fertilized egg will not be able to gain a foothold in the uterine cavity or will do so incorrectly.