Doctors count the start of pregnancy not from the expected date of conception, but from the time of egg maturation and the onset of ovulation. That is, it turns out that the 2nd week of pregnancy may not be such, but only testify to the preparation of the body for this process. But if a woman plans to conceive a child, she needs to be attentive to her health and follow the important days of the cycle. If we talk directly about pregnancy, then such a count is obstetric. Embryonic weeks are counted from the date of the expected conception. Thus, in the first week, fertilization and advancement of the egg through the fallopian tubes into the uterus occurred. But in the second week, the fetal egg is fixed in the uterus and the development of the embryo begins.