How pregnancy occurs
The pregnancy takes place two weeks after the first day of the last menstrual cycle. A mature egg in one of the ovaries is transferred to the fallopian tube. This stage is called ovulation. The pregnancy occurs by fertilizing the egg through one sperm between the millions of animals produced by the male during sexual intercourse, This fertilization occurs with the union of the sperm with the egg to form a fertilized egg. This fertilized egg is exposed to a series of equal divisions that lead to differentiation of the cellular mass and helps it to implant and nest on the wall of the uterus. Drejia fully fetched the fetus during the nine months, showing normal signs of normal fetal growth as it emerges from the uterus.
Pregnant women begin to be calculated from the first day of the last menstrual cycle, and women often do not feel pregnant during the simple period of fertilization and fetal implantation. They may not even feel it before four weeks of pregnancy or the absence of their next menstrual period as a symptom Pregnancy.
Stages of fetal development in weeks
The fetal cycle of life in the womb of the mother undergoes many changes that eventually produce the human body. The entire pregnancy period is forty weeks, starting with the first day of the last menstrual cycle, and lasts until the fetus goes down and goes to birth. :
The first stage
Starting from the first week until the end of the twelfth week.
First and second weeks
The stage of pregnancy begins with the interruption of the menstrual cycle, which represents the stage of the descent of the egg, or the so-called ovulation, to meet the sperm that reaches through the egg channel fertilizing the egg. The egg then begins to divide in a sequential manner, producing a fertilized egg. The egg fertilization follows several equal divisions representing the composition The embryo of the human embryo, to migrate this cellular mass to the uterus, and begin to implant in its belly with a process called culture or nesting.
The third and fourth weeks
After the semen meets the egg and the fertilized egg, the process of division begins with the growth of the fertilized cell into two cells, then four, then eight cells, including sixteen cells. This stage is called thymus. During the third week, the fertilized cell moves through the fallopian tube, To begin the process of implantation in the uterine wall, the fertilized egg appears after the implantation process in the form of two different parts, one of which is the food carrier or the placenta, the other is the embryo that begins to bend and its cells begin to multiply to receive each cell in which the fetal organs are formed.
From the fifth to the eighth week
In this period many of the developments of the fetus occur faster than the previous weeks, where the heart starts to pulse and blood flow is organized, and the upper and lower limbs appear in the form of sprouts, and some internal organs begin to grow as the liver and kidneys and intestines, and the following week, Simple, where begins to form the nostrils and bony ears and the place of the eyes, and begins to separate the limbs from the body of the fetus, and appear as the sight of the paddles, and begins the fetus with his simple random movement is not tangible for the mother.
At an advanced stage in this period, the heartbeat of the fetus is shown by the ultrasound device, and the circulation of the circulatory system begins regularly, with the growth of internal organs such as kidneys, liver and brain with the development of physiological functions, and the growth of the limbs with the emergence of protrusions represent the fingers at a later stage in The embryo’s growth begins with the formation of a simple form to show its human appearance, giving it a human form, and in the meantime the size of the head is the largest part of it.
From the ninth to the twelfth week
At the beginning of this period, the growth of the placenta is relatively complete, as it is able to produce the necessary hormones in the pregnancy process. The fingers and toes appear more clearly, the shape of the wrists and ankles appears, the limbs grow and the inner structure of the ear is complete. Via an ultrasound device.
The growth of internal organs such as the heart, kidneys, liver and brain, and thus the performance of its physiological functions fully, and the emergence of the shape of the forehead and mediated in the head of the fetus, and start the bone stiffness, with the formation of the buds of the teeth under the gums , And the skin of the fetus is transparent; the blood vessels appear through it easily, and in this period the growth of the fingers of the fetus and its separation from each other, with the continuation of the movement of the fetus and his light,
The embryo’s breathing during this period is limited to what it gets through the amine fluid. This fluid represents the actual environment of the fetus, where the fetus sheds its excretions when its kidneys are complete, and the brain’s growth velocity slows as compared to previous weeks.
The second phase
It starts from the 13th week until the 24th week.
The thirteenth to sixteenth week
The physical and functional changes continue during this period, as the vocal tendons and teeth begin to grow and develop, and the fetal ear development is completed, where they can hear and communicate with their mother’s voice, and develop the fetal muscle capacity in the swallowing process. As the liver and spleen continue to grow, the liver begins to excrete its bile. The spleen produces red blood cells, and the fetus is more flexible and active, increasing its movement, but it is not as strong as the mother.
In this period, the fetus’s sex can be identified through the ultrasound system. The legs grow longer than the arms. The joints begin to move smoothly. The limbs become more flexible in proportion to the flexibility of the muscles. During this period, the alveoli begin to form, Soft and lint on the skin of the fetus, and activate the movement of arms and legs, increases the strength of strikes, and the mother feels fetal movements and location, and in the meantime begins thyroid gland organizational work, producing special hormones regulate the metabolism of the body of the fetus.
Week seventeen to twenty
At the beginning of this period, the hair appears on the head of the fetus, its eyebrows and eyelashes. The metabolism begins as a result of activation of the thyroid gland and its secretion to the important hormones of the fetus and its vital processes. Most of the internal organs in the fetus’s body, such as the urinary system and circulatory system, continue to function. , And becomes more affected and responsive and a sense of light, followed by the stability of the ears in place on the sides of the head, and consists of the female genitalia grow the vagina and the fallopian tube in the uterus of the fetus, and increase the strength of the fetal movement, The nerve cells responsible for the five senses begin to settle in place, as does the growth of the size of the neurons, and the neural connections become more dense and interrelated.
At the end of the month, the fetus is able to perform the procedure for the first time, where the stool material consists of dead skin residues and digestive secretions remaining in the intestines, this stool is of nature and composition does not harm the fetus or his mother, in addition to the beginning of permanent teeth behind the teeth .
Week twenty-first to twenty-fourth
At the beginning of this period, the entire body of the fetus becomes hair to provide protection. The fetus begins to feel what surrounds it as a result of the development of its sense of touch. It becomes able to feel the wall of the uterus when it is touched. It also begins to hear and respond to external sound effects. The fetus grows at a height of about 30 centimeters by the end of the twenty-third week. Its weight increases by 80 grams between the 22nd and 23rd weeks to about six grams. The fetal skin is gradually reduced by the appearance of pigmentation on the skin. This period is the inner ear that controls the balance of the body.
Third stage of pregnancy
Starting from the beginning of the twenty-fifth week until birth:
Week Twenty-fifth to Twenty-eighth
In addition, the nasal connections of the ears, and the primitive attempts of the embryo to carry out the breathing process, may swallow small quantities of water. At the end of this period, It is about thirty-six centimeters long and weighs up to about nine hundred grams. At the end of this period, the child is able to sleep and wake up regularly with the accumulation of fat under his skin.
Twenty-ninth to thirty-second (eighth month)
The body of the embryo is a white fatty layer called paint. This layer protects the skin of the fetus from its intestinal tract. This layer gradually disappears gradually, in addition to the epidermal layer that previously covered its skin. At the end of this period, the uterus prepares the embryo for the birth process. Fetal head down.
Week Thirty-third to the end of the thirty-sixth week
At this stage the initialization takes place to take birth position, embryo descent into the pelvic area, complete brain construction and stiffness of the bones, and move the testicles from the abdominal cavity of the male fetus towards the scrotum.
Week 37 to 40
The embryonic layer begins to disappear completely from the skin of the embryo, with the formation of a fatty layer regulating the temperature of the fetus and prepare for its exit to the world, and at this stage all organs and organs of the fetus is fully developed except the lungs, to complete the growth process after birth, and in this period the weight of the fetus has arrived And the feces begin to form inside the intestines, and the fetus is placed under the mother’s pelvis, the head is headed downwards, and the uterus prepares to enter the labor and delivery stage.