Is it often the case that there can be a period of 3 days in pregnancy?

Bleeding in pregnancy is rare and is generally a cause for concern as it can be a sign of complications. In the vast majority of women, complete amenorrhea is the first and strong signal that pregnancy has occurred. Menstruation usually lasts no less than three days and no more than 7 days. In a given woman, the menstrual bleeding profile is generally repetitive in subsequent cycles. In some cases, so-called implantation bleeding (implantation of the embryo in the uterine wall) may occur only in about a third - a quarter of women. It occurs approximately between 6-12 days after fertilization. Implant spotting is usually much shorter than the period, it can last even only a few hours, and up to a maximum of 3 days. It is also definitely less abundant than regular menstruation. A blood test taken 2 days before the expected date of menstruation should already show pregnancy if it happens. It remains to be decided whether to repeat it. I enclose additional information about the tests: https://www.gdziepolek.pl/kategorie/test-ciazowy

To @Czarna:

A period that occurs earlier than usual can be caused by a variety of factors, such as stress, hormonal changes, or certain medications. It is not a direct symptom of pregnancy. A pregnancy test taken 8 days after intercourse may give a negative result because the level of the hCG hormone is too low to detect at that time.

If you suspect pregnancy, it is advisable to wait a few days and repeat the test, especially if your period does not recur.