In recent weeks, on the Asalvo blog, we have reviewed what changes occur in a woman's body when the pregnancy process begins. We have seen that, although the first two weeks are also part of the gestational process, we know that the baby is not yet present, but rather we are witnessing the moment of “preparing the ground.” Now yes, the pregnancy itself begins at the beginning of week 3. Immediately after fertilization, the interior of the egg presents two cell nuclei: the nucleus of the egg with the female genetic factor and the head of the sperm with the male genetic information. Their fusion creates the unique genetic code of a new human being. Shortly after, this zygote begins to divide, thus becoming the starting point for billions of other cells.
Safe Tip: Folic acid (vitamin B9, B11) is vital for the baby's organs to develop healthily.
On the second day after fertilization, this cell group consists of four cells, one day after eight cells, and so on. In the third week, its appearance resembles that of a blackberry (Latin: morula), which is why scientists call the fertilized egg morula. A day later, a cavity forms within the cell group: the morula has become a complex cellular structure (blastocyst) made up of two different types of cells:
The embryoblasts become the true embryo: the baby carries this scientific name until the end of the first trimester, only after all important organs have been formed will it be called a fetus. The placenta develops from trophoblasts and, together with the umbilical cord connected to it, later takes over the feeding and oxygen supply of the baby and removes waste from its metabolism.
During pregnancy week 3, the embryo moves tirelessly from the fallopian tubes to the uterus, where it usually arrives at the beginning of the following week of pregnancy. When it reaches the uterus, it already consists of about 70 to 100 cells. The external signs of pregnancy are not yet visible at this early stage. At week 3, most women still do not know they are pregnant.
However, fertilization involves a large number of hormonal changes that ensure the maintenance of the pregnancy and the development of the embryo. Immediately after ovulation, the follicle assumes a new function as a corpus luteum: It begins to produce progesterone, responsible for the thickening of the endometrium and, therefore, crucial for the nesting of the egg.
Regarding the mother, during the third week of pregnancy there are no major changes in her body and she does not feel anything special yet. On a physical level, certain symptoms may occur, which are the same as those we mentioned in the post about the second week of pregnancy. Likewise, in most cases there is not even a suspicion of pregnancy.
and this is how we end week 3 of pregnancy, where we can now begin to talk about the presence of the blastocyst for now, which in the future will become a baby. Each week that we discover is more exciting and more intense than the previous one. Do you want to read the next installment of Asalvo's week-by-week pregnancy?
