With every week of pregnancy, limits develop for your baby. You may hear your doctor talking about specific stages of pregnancy in specific medical terms such as the fetus, embryo and zygote. These define your baby’s developmental stages. You can read the article to learn what these terms mean, what your baby is going through along the way.
What is a Fetus?
Life begins with the merging of the female egg with the sperm cell from the male. This situation, which is also defined as fertilization, is the first step in human formation. After fertilization, which constitutes the initial period of pregnancy lasting approximately 40 weeks, the baby begins to grow and develop in the womb. In this period, which lasts for 9 months and 10 days, the baby is defined by different names such as zygote, embryo, fetus. Before explaining what the fetus means, it is necessary to know about zygote, embryo, fetus ordering. The period starting with the fertilization of the female egg with the male reproductive cell sperm and until the end of the second week is called the zygote period. During this period, the egg of the expectant mother, fertilized with the sperm cell of the father, begins to multiply by dividing with great speed.
In other words, with the combination of these two cells, 23 male and 23 female chromosomes come together and turn into a single cell structure. After this point, the zygote begins to multiply by dividing rapidly. This proliferation can be defined as the first step taken for the formation of the tissues and organs of the baby in the future. However, the zygote, which is as big as the head of a needle, multiplies by multiplying so rapidly during this period that growth and reproduction at this speed never happens again in any stage of human life. These layers of zygote, consisting of 3 different layers, play an important role in the formation of different organs of the baby. After this stage, the embryo period begins, which will last from the 3rd week after fertilization to the end of the 8th week. The creature, which has reached approximately a peanut size, is now referred to as an embryo. The embryo, which begins to form slowly, is located in a pouch filled with amniotic fluid that protects it from external factors. This creature is able to swim by flapping its legs in amniotic fluid, that is, it is movable. During this period, the formation of tissues and organs begins. During the embryo period, the baby gains a human-like appearance with a bean-like appearance, head, trunk, arms, legs, hands and feet. From the 9th week of pregnancy, the embryo is now referred to as a fetus in medicine. In other words, the baby is referred to as the fetus in the process from the 9th week of pregnancy to the birth. This period is defined as fetal period or fetus period. In the first week, which began to be defined as a fetus baby, the eyes of the fetus are far apart, the head is large and the legs are short. However, during the remaining period of pregnancy, the development of the fetus continues rapidly, and when she is born, she is born as a fully developed, fully functioning person. Now this is not known as a living fetus, but as a baby. The question of what is a fetus that pregnant women frequently wonder can be answered in this way.
How is Fetus Development?
The baby is defined as a fetus during the 9th week until the birth. Fetus development varies greatly from week to week. In the 9th week, the face of the fetus is wide, the eyes are on the sides of the head, the head is larger than the body, and the legs are short. By the 12th week, the extension of the arms of the fetus is completed. Urine begins to form and the blood-making function passes from the liver to the spleen. In addition, gender discrimination is at a level that can be made. In this period, questions such as what is the female or male fetus can be asked. The sex of the baby can be learned by vaginal ultrasound examination after the 12th week. Ear and skeleton formation begins as of the 16th week. Hair may begin to form on the scalp. Depending on the development of the body, the head becomes more proportional. By the 20th week, the growth slows down, the lengthening of the legs is completed, and the baby’s movements become palpable. The first body hairs, defined as lanugo, are formed, and the baby’s body is covered with an oil-like substance known as a caseous varnish.
The uterus is formed. As of the 25th week, the increase in weight of the fetus becomes evident. Its skin is transparent and wrinkled. Therefore, blood vessels are visible. Fast eye movements are seen in the fetus, where nail formation begins. By the 29th week, hair and body hair become more evident. Respiratory movements begin, and due to the formation of fat under the skin, the fetus becomes able to control body temperature for the first time. Blood production is transferred to the bone marrow. Babies born as of this week can survive thanks to newborn intensive care units. As of the 34th week, the light reflex is seen in the fetus, the skin is free from wrinkled appearance and smooth. By the 38th week, the grip reflex develops. The testicles of male fetuses descend into the testicle bag. Oiling increases. 40-41. Birth takes place in weeks, and the fetus is now referred to as a baby.