At the beginning of this week the fertilization of your egg took place. This means that a sperm cell has succeeded in penetrating the egg cell wall. The hereditary characteristics of the sperm cell and oocyte are mixed and the sex of the baby is determined. This process of fusion of the cells is called 'conception'. The fertilized egg is also called 'zygote'. If you 3 weeks pregnant the fertilized egg is going to nest in the womb.
3 weeks pregnant: The way to the womb
If the egg is fertilized, nothing happens for 24 hours. After this, the egg cell will divide until it is a small ball of hundreds of cells. This ball looks like a berry and is called 'blastocyst'. The blastocyst is slowly pushed to the uterus by the fallopian tube. This takes about 5 to 7 days, although it actually only involves a piece of a few centimeters. The blastocyst is currently about 0.1 to 0.2 millimeters in size and attaches itself to the uterine wall.
Implantation in the womb
The inside of the egg cell has so-called 'adhesive flakes'. These suture flakes grow out of the placenta at a later stage when the clump of cells (the blastocyst) settles in the uterine wall.
Until now, as a woman, you do not notice anything that has happened in your body when you are 3 weeks pregnant. But at the moment the egg starts to implant you can get a slight bleeding.
This is also called implantation bleeding. The bleeding is caused by the fact that the uterine wall is thick at the time of implantation and is vigorously perfused. It is possible that a blood vessel tears through the implantation, which leads to blood loss.
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Women who do not know they are pregnant confuse this bleeding with a normal period of time, although the amount of blood you lose is a lot less. However, the chances are higher that you do not have bleeding, only 1 out of 3 women has this. During the implantation, the cell division of the egg cell continues until billions of cells have been formed. From that moment on the fertilized egg is called an embryo.
Do you want to know how your baby is developing? Then follow the growth of your baby week by week in our pregnancy calendar.
Protection of the embryo
If you are 3 weeks pregnant your body will produce a lot of hormones. This will change your hormone balance which could later be the cause of, for example, morning sickness. This is very annoying, but just think: these hormones are essential to ensure that your embryo is protected. Without these hormones, your body would see the embryo as an intruder and try to destroy or destroy it.
In addition, the hormone progesterone ensure that the uterus is no longer penetrated and your embryo is safe. At the same time the mucus plug in your uterus (which is already present) changes. This mucus plug ensures that the uterus is closed to prevent infections.