How is a fetus developed in the first month?

First week

During the first week, the fertilized egg travels through the fallopian tube and reaches the uterus. It will then begin to divide into smaller cells, forming a hollow ball of cells called a blastocyst. The blastocyst will then attach itself to the wall of the uterus.

Second week

During the second week, the blastocyst begins to grow and divide into two layers: the inner cell mass and the outer trophoblast layer. The inner cell mass will become the embryo, while the trophoblast layer will become the placenta. The placenta is responsible for providing nutrients and oxygen to the embryo, and for removing waste products.

Third week

During the third week, the embryo begins to form the basic structures of the human body. The neural tube, which will eventually become the brain and spinal cord, begins to develop. The heart also begins to beat, and the tiny embryo begins to move around.

Fourth week

By the end of the fourth week, the embryo is about the size of a poppy seed. The eyes, nose, and mouth have begun to form, and the limb buds have begun to appear. The embryo is also starting to develop its own circulatory system.

Development beyond the first month

After the first month, the embryo will continue to grow and develop rapidly. By the end of the second month, the embryo will be about the size of a kidney bean and will have all of the major organs in place. By the end of the third month, the embryo will be about the size of a peach and will be able to move around more. By the end of the fourth month, the fetus will be about the size of a banana and will be able to suck its thumb and make other movements.

By the end of the first month, the fetus has developed from a fertilized egg into a tiny embryo with all of the major organs in place.