If the patient normally has regular periods, the number of days of pregnancy is counted from the first day of the last menstrual period. If the patient has irregular periods, the number of days of pregnancy is based on the time of the first positive urine HCG test or the number of days provided by the first ultrasound examination of the pregnancy. If these tests are not available in early pregnancy, a rough estimate based on femur length is needed in mid-pregnancy, although this value is not particularly accurate at this time. After pregnancy, it is necessary to carry out regular maternity check-ups, which, in addition to the necessary ultrasound examinations, also include the appropriate auxiliary blood tests, the main purpose of which is to detect in time whether the pregnant woman and the fetus have shown any abnormalities during pregnancy, which can largely reduce the risks to the mother and child.