Intrauterine growth is a fundamental stage of life since many factors at this time can condition all future growth. The growth of the baby in the womb includes two periods: embryogenic and fetal growth.
The growth and development of the future baby are characterized by an increase in size, an increasing structural complexity and the maturation of functions. How can we know if it is growing properly in the uterus?
We know that through ultrasound during pregnancy the approximate weight of the baby is estimated based on the measurements of three parameters: the abdominal circumference, the perimeter of the head and the length of the femur.
In addition, based on averages, there are calendars to know weight and measures during pregnancy and formulas to calculate fetal weight according to the week of gestation.
Thanks to these estimates and measurements through ultrasound we can know if the fetus develops according to their gestational age, or if it will be more or less large, that is, to know more about the growth of the baby in the womb , in its different stages, about which we talk in detail below.
The development of the embryo
Recall that embryogenesis is the complex generative process that leads to the formation of a multicellular organism, plant or animal, from the zygote.
Human embryogenesis is defined as the process that begins after the fertilization of the gametes to give rise to the embryo, in the first stages of development of multicellular living beings. In the human being, this process lasts about eight weeks, at which point the product of conception finishes its first stage of development and becomes known as a fetus.
From the fourth week, the embryo begins to develop the vestiges of the future organs and apparatuses, and in this stage it is very sensitive. A phase of frantic growth begins that lasts another month, during which all the organs, systems and devices of the future adult organism are outlined.
During the period of embryonic development the different organs of the future fetus are formed and characterized by an increase in the number of cells (it grows almost exclusively by hyperplasia, that is, the increase in size of an organ or of a tissue because its cells have increased in number).
The growth of the fetus
In the period of fetal growth, there is an intermediate phase of hyperplasia and hypertrophy, with an increase in cell size and a decrease in the mitotic index or cell division. Hypertrophy is the increase in the size of an organ when it is due to the correlative increase in the size of the cells that form it ( the organ has larger cells , and not new ones). It is distinguished from hyperplasia, in which case an organ grows by increasing the number of cells, not by a larger size of the cells.
The growth curve is characterized by a progressive increase in the speed of growth in length, which reaches its maximum approximately at week 18, while the maximum increase in weight takes place towards the final weeks of pregnancy.
In the final stretch of pregnancy the baby grows at an accelerated pace, increasing weight between 200 and 300 grams per week. In the last stage of pregnancy, organs and tissues are already formed, and there is an accumulation of fat under the delicate skin, which will help you to better regulate your body temperature when you are born.
At the beginning of the week 35 weighs about 2'400 kilos and measures 47 cm, although at this height there may be a large difference in size between different babies. In week 38 the estimated measurements of the baby are 50 centimeters and 3'200 kilos. In week 40 the baby measures 52 centimeters from the head to the feet and weighs about 3,400 kilos.
Of course, these are approximate average measures, and it will not be until it is born when we know how much the baby is measuring. Even the latest ultrasounds that estimate the fetus's measurements can be wrong .
The growth and development of the future baby are characterized by an increase in size, an increasing structural complexity and the maturation of functions. How can we know if it is growing properly in the uterus?
We know that through ultrasound during pregnancy the approximate weight of the baby is estimated based on the measurements of three parameters: the abdominal circumference, the perimeter of the head and the length of the femur.
In addition, based on averages, there are calendars to know weight and measures during pregnancy and formulas to calculate fetal weight according to the week of gestation.
Thanks to these estimates and measurements through ultrasound we can know if the fetus develops according to their gestational age, or if it will be more or less large, that is, to know more about the growth of the baby in the womb , in its different stages, about which we talk in detail below.
The development of the embryo
Recall that embryogenesis is the complex generative process that leads to the formation of a multicellular organism, plant or animal, from the zygote.
Human embryogenesis is defined as the process that begins after the fertilization of the gametes to give rise to the embryo, in the first stages of development of multicellular living beings. In the human being, this process lasts about eight weeks, at which point the product of conception finishes its first stage of development and becomes known as a fetus.
From the fourth week, the embryo begins to develop the vestiges of the future organs and apparatuses, and in this stage it is very sensitive. A phase of frantic growth begins that lasts another month, during which all the organs, systems and devices of the future adult organism are outlined.
During the period of embryonic development the different organs of the future fetus are formed and characterized by an increase in the number of cells (it grows almost exclusively by hyperplasia, that is, the increase in size of an organ or of a tissue because its cells have increased in number).
The growth of the fetus
In the period of fetal growth, there is an intermediate phase of hyperplasia and hypertrophy, with an increase in cell size and a decrease in the mitotic index or cell division. Hypertrophy is the increase in the size of an organ when it is due to the correlative increase in the size of the cells that form it ( the organ has larger cells , and not new ones). It is distinguished from hyperplasia, in which case an organ grows by increasing the number of cells, not by a larger size of the cells.
The growth curve is characterized by a progressive increase in the speed of growth in length, which reaches its maximum approximately at week 18, while the maximum increase in weight takes place towards the final weeks of pregnancy.
In the final stretch of pregnancy the baby grows at an accelerated pace, increasing weight between 200 and 300 grams per week. In the last stage of pregnancy, organs and tissues are already formed, and there is an accumulation of fat under the delicate skin, which will help you to better regulate your body temperature when you are born.
At the beginning of the week 35 weighs about 2'400 kilos and measures 47 cm, although at this height there may be a large difference in size between different babies. In week 38 the estimated measurements of the baby are 50 centimeters and 3'200 kilos. In week 40 the baby measures 52 centimeters from the head to the feet and weighs about 3,400 kilos.
Of course, these are approximate average measures, and it will not be until it is born when we know how much the baby is measuring. Even the latest ultrasounds that estimate the fetus's measurements can be wrong .
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