Katarzyna, as far as I know, in practice gynaecologists use several methods that allow them to determine the age of the embryo and the date of fertilization. Ultrasound in the first trimester is considered the gold standard for assessing the age of the embryo - the doctor measures CRL to assess the age of the fetus and the potential date of fertilization. From what you wrote, the doctor put it this way, giving data in cm that the fetus looks 8 weeks and 4 days old. In addition, the date of the last menstrual period is taken into account. You know this date - 14.06. It is most often assumed that the day of conception is 14 days after the first day of the last menstrual period (assuming a regular 28-day cycle). If you have any doubts, I encourage you to contact this doctor, he will be able to dispel any doubts you may have, because he was the one who performed the examination.

I forgot to add that my due date according to ultrasound is 20.03.2025

Mrs. Anna, and on what basis does the doctor determine the day of fertilization? Isn't it the case that the ultrasound should show lower parameters, e.g. if I'm in 8 t4 days, I shouldn't hear from the doctor that the embryo looks like 6 t 4 days?