What are the stages of fetal development by weeks?

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 Fetal development stages by weeks




an introduction


Pregnancy is one of the most important divine laws established by God Almighty in preserving the descendants of mankind, 

and God Almighty used it in the selection of mammals, and the Almighty said: (O people, if you have doubts about the Resurrection, then create us. You are dirt the price of seed. Created and uncreated, 

we can explain to you That determines in the womb what we are going to do for a fixed period, and then we deliver you as a baby.

The importance of knowing the stages of fetal development



It is a matter of precious human life and soul while growing up; Therefore, a pregnant woman must understand the stage of fetal development to link the growth of the fetus with the accompanying symptoms to increase the bond and relationship between mother and daughter. 

The fetus, and increased her insistence and interest in him, which gave her a unique opportunity to reflect on the poem, God said, meditating on the creation of God, the Almighty and the Sublime: (In yourselves you do not see).

Fetal development stages


The journey of embryonic development and the formation and growth of its organs begins with the first fertilized cell after the first week of fertilization; 

So we will include these stages from the second week to the fortieth week to show the composition of each organ of the body, the date and start of developmental and functional work.



first month


In the third week: the pregnancy is not visible to the naked eye, and the fertilized egg leaves its place, migrates through the fallopian tubes into the uterine cavity, and descends into the lining; This is a precursor to the start of the nesting process.

The fourth week: This week the fetus is characterized by rapid primitive growth, and it can be seen with the naked eye that there is a layer of the membrane around the nucleus of the fetus called the deciduous membrane; Because the fetus falls with the placenta as soon as it comes out.

second month


The fifth week: During this week, the size of the fetus gradually increases, and the length of the fetus reaches about 2 mm, the spine begins to form, and the primitive nervous system begins to form.

  • Sixth week: This week is considered the key to the growth of the fetus, as many organs appear and form, such as the head, the abdominal cavity, the thoracic cavity, the primitive brain, the spinal cord, and the spine. The heart, as well as the stomach and intestines, begins to appear a little at the weekend when the fetus is about six millimeters long.
  • Seventh week: This week continues the growth of the organs that appeared in the previous week; It is clearly visible in the functional structure, the contours of the arms and legs appear, the masses of joints formed by the fingers, the growth and development of the blood system; Blood vessels begin to flow to the head and other parts of the body. Diffusion, start the cycle, enough blood movement, heartbeat, and lung formation occur on both sides of the chest, the nervous system develops to complete its growth, except for the peripheral and cutaneous nerves, the eyes appear closed, and there is no incision, the head is round, I am almost done. This week, complete By the end of the week, the fetus grows about 1.3 cm in length.
  • In the eighth week, the growth of the fetus increases this week to reach a length of about 2.2 cm, while its total size is still concentrated in the head, where the formation of the nasal cavity and nasal openings begins, and the middle ear is formed without them. the outer ear, and at first the jaws fuse, the limbs of the fetus continue to develop; Knee contours show shoulders and elbows, get ready for your first simple posture movement.


the third month


  • The ninth week: This week the fetus grows to about three centimeters in length and may weigh up to two grams. The movement of the fetus begins, but it does not appear to the mother due to the growth of the limbs, as well as the growth and development of other organs, as the eyes appear and become complete during the past few weeks. The growth of the shape of the mouth and nose.
  • the Tenth week: During this week, the weight of the fetus increases to five grams and the length increases to about five centimeters. The umbilical cord grows and stimulates blood circulation in the arteries and veins, and the nucleus of the placenta begins to form. Other parts of the body continue to grow because the eyes are in clear shape. The fingers are different, but they are connected to each other because there is a membranous substance on the feet of birds like ducks that connects them, and the outer ear begins to form to reveal the nucleus of the small pinna.
  • Eleventh week: This week is considered important because it provides an indication for estimating the sex of the fetus; This week, the male and female genitals are clearly formed, the middle and inner ears are complete by the end of the week, and the outer ear continues to grow and develop, and the rest of the limbs; Where is the fetus active this week and the heart is developing; It is about five and a half centimeters long and weighs ten grams.
  • Twelfth week: The rest of the body’s growth process continues, and the fetus’s weight increases to about eighteen grams, and by the end of the week it reaches about seven centimeters in length. Keep leaning forward.


Fourth month


The thirteenth week: The size of the swelling in the uterus appears clearly this week in the form of a cyst-like swelling that emerges from the pelvis, 

and is formed because it contains the fluid in which the fetus swims, called the amniotic fluid, and some parts such as the neck, the outer ear, the growth of the lungs, 

liver, kidneys, intestines, etc. . Organs grow and enlarge, and the fetus weighs thirty grams and is about seven and a half centimeters long.

The fourteenth and fifteenth week:

  • Organs continue to grow and develop functionally, and the fetus is fully formed but has not yet reached the mature form that enables it to perform full life functions.
  • Sixteenth week This week, the sexual characteristics of the fetus appear clearly, and since the formation of the limbs has been completed, and the movement of all joints, their movement becomes so intense that the mother feels it sometimes. The growth of the remaining organs increased until the fetus was about sixteen centimeters long and weighed one hundred and thirty-five. Gram, because the entire body of the fetus is covered with fine hairs called villi, and the organ continues to grow for three weeks without any changes in organ function.
  • In the twentieth week: the volume of the amniotic fluid increases in a way that allows the movement and rotation of the fetus. The length and weight of the fetus double to about twenty-five and a half centimeters in length, and its weight is about three hundred and fifty. Grams. The process of fetal development continues for the next three weeks.


The fifth and sixth months


In the twenty-fourth week: the organs of the fetus as a whole mature, and the symptoms of pregnancy appear in the abdomen; Because of the increase in the size of the fetus, 

its length became about 33 cm, and its weight was about 750 grams. In the following four weeks, the growth process did not show any morphological changes.

The seventh and eighth months


The twenty-eighth week: This week the fetus is alive, and his death is not a miscarriage, but rather death. Where it is covered with a white fatty substance to protect it, 

as the fetus grows to about seven-thirty centimeters long and weighs about nine hundred grams, and continued to grow during the following four weeks.

The ninth month


Thirty-sixth week: This week the fetus’s growth is complete, including the lungs, the fetus is born normally, the fetal head is close to the ideal position of the pelvis, and the testicle comes out of the abdominal cavity and falls into the scrotum. 

Because of the accelerated growth rate, the length of fetal growth this week may reach up to About forty-six centimeters and a weight of two and a half kilograms, 

after this week, the fetus will be excreted within the natural time of birth, at the time that God Almighty wills, i.e. the name mentioned in the text. In the previous verse, the gestation period is up to forty weeks, which is the time of normal conception.

Forty weeks: This week the fetus gains weight at a rate of three and a half kilograms, and its body length is half a meter; This is due to the storage of subcutaneous fat in the last few weeks, 

which is the length of the fetus's head. It increased in size from 2 to 4 centimeters, the nails were prominent, the body had gone the surrounding fluff, and some traces remained on the shoulders and forehead.