This guide is designed to educate about the growth and development of the child or baby in the womb and provide valuable information for expectant mothers and pregnant women.
Fertilization of the egg by the sperm.
A fetus or fetus is an embryo in in pregnancy after the formation of internal organs. Development begins at the 11th week of pregnancy and ends at birth. Click to enlarge. Newspaper reports of recent times report that science is repeatedly succeeding in observing the beginning of human life outside the womb in experiments and preserving it for a few weeks. This is the artificial fertilization of a human egg cell with a male sperm cell and the subsequent development of the germ under artificial conditions largely adapted to the organism. These successes of medicine, should be the occasion for our consideration of human development. The so-called conception normally takes place in the vicinity of the ovary and the fallopian tube, where the union of a mature female egg, capable of fertilization, with a male sperm cell takes place approximately in the middle of the menstrual cycle. Since eggs are capable of fertilization for only a few hours, while sperm cells are capable of fertilization for about two days, the greatest possibility of fertilization in a normal 28-day menstrual cycle is from the 12th to the 16th day, calculated from the first day of the onset of menstruation. The fact that conception may exceptionally take place on other days of the menstrual cycle may be caused by hardly noticeable deviations in the complicated sequence of the body for fertilization. As is well known, the ovaries are also subject to regulation by the nervous system, and shifts in the menstrual cycle as a result of excitement, climatic changes during travel, anxiety, illnesses and the like are no longer a cause for concern, even for the medical profession. Likewise, most will be aware that one can gain closer insight into the function of the ovaries and ovulation through regular temperature measurements taken over weeks and months.
Cell division of the ovum
But back to our fertilized egg cell, whose further development we want to follow. It receives its final maturity only at the moment of the penetration of the spermatic filament, and only then the union of the nuclei of egg and spermatic filament, the conjugation, begins. Immediately after this, the numerous cell division processes occur, giving rise to the first furrowed and embryonic cells, each of which contains an equal number of nuclear loops (chromosomes) from the mother and father of the developing child. During transport through the fallopian tube, also known as the tube, the fertilized egg initially has a smooth envelope that prevents premature implantation by this route. Rhythmic movements of the fine muscles in the fallopian tube wall, as well as those of the inner ciliated cells, slowly push the egg, which is nestled between the soft folds of the tube, forward to the uterine cavity within 5-10 days. In the last period of this migration, the envelope becomes villous, and thus the now villous egg of the total size of a pinhead has the ability to settle in the loosened prepared mucosa of the uterus. These villi are able to dissolve the fine tissue of the uterine mucosa and supply the dissolved substances to the germ as nourishment. It can be said that the egg literally eats its way into the mucosa, after which this entry port is closed by a small blood clot. The young germ then continues to grow under the surface of the mucous membrane as if in a nest, which eventually bulges more and more into the uterine cavity. Meanwhile, a hollow sphere including invagination has formed from the approximately massive cell sphere, which allows the special development of organs and forms to mature from the so-called germ shield.
Development in the uterus
Essential for the further nourishment of the germ is placentation: the creation or development of the placenta. This organ, which is newly formed for each pregnancy and completely removed from the womb after the birth of the child, is responsible for all further nutrition, respiration and excretion of the embryo. The uterine mucosa and the germ participate in the formation of the placenta.As already mentioned, the germ forms so-called villi on the surface of the egg wall, which, however, remain only at the base after implantation, i.e. at the point connected to the germ bud by the umbilical cord. In this area, a blood lake is now formed, so to speak, from which the villi supply the germ with everything necessary for life. Subsequently, the maternal mucous membrane grows against it and numerous ventricles are formed, from which finally a complicated network of vessels is formed, in which, as it were, necessary building materials are secreted, prepared and exchanged with the child’s excretory substances. Since this is also especially true for the passage of oxygen and carbonic acid, the placenta fulfills the function of a lung for the embryo, which cannot breathe. In addition, the placenta produces, for example, all known sex hormones, which are necessary for the protection of the expectant fruit until birth. The latter, however, should only be mentioned in passing, as it would be going too far in this context to go into the entire maternal hormone balance during pregnancy. Not to be left unmentioned is the storage capacity for all kinds of substances, especially vitamins, so that the placenta is considered the organ of the human body richest in vitamins. Contrary to all other customs, special conditions prevail in the umbilical vessels (which include two arteries and one vein), which are responsible for a connection between the supply depot of the placenta and in the embryo. In the umbilical arteries, the fetal blood enriched with carbonic acid and degradation products flows into the vascular territory of the placenta, while the umbilical vein carries the blood provided with oxygen and nutrients into the circulation of the germ.
Growth of the baby, 4th month of pregnancy.
Brain development begins in the fetus during the 3rd week of pregnancy. By the end of the 8th week, the brain is almost complete. When the baby is born, brain development is far from complete. Click to enlarge. With increasing duration of pregnancy and at the same time progressive growth, towards the end of the fourth month of pregnancy, the initial cavity of the uterine body is completely filled. In these parts the egg skin also sticks to the uterine mucosa. The embryo is completely in the amniotic sac, where the amniotic fluid is formed. The amniotic fluid reaches its maximum amount of 1 1/2 to 2 liters around the middle of pregnancy, while by the time of delivery it is only 1/2 to 1 liter. About exact dates as well as the extent of development of individual organs appointed scientists have written highly interesting treatises and extensive textbooks. In today’s context, we would like to mention only a few guidelines on this subject, which are so often the subject of questions from expectant mothers in our medical consultations. At the end of the first month of pregnancy, the body shape typical of the human germ develops. There is already a brain and heart anlage, the eyes, limbs and spleen anlage, as well as the anlage of the four main lobes of the liver. The total length of the germ is 1 mm. In the second month of germination there is a strong growth in length, the heart begins to beat 60-70 times a minute, the human appearance becomes more recognizable, the length is 2-4 cm. From the third month, the embryo is also called a fetus, the thyroid gland begins to work, the external sexual organs show the first sex differences. At the end of the third month the length is 9 cm, the weight is 33 g. In the fourth month, the hair systems of the so-called woolly coat can be seen all over the body, bile secretion begins. The length is 16 cm, the weight is 100 g.
Growth of the baby, 5th month of pregnancy.
It in the fifth month of pregnancy, listening to the fetal heart sounds can be heard at 120-140 beats per minute. Pregnant women feel the fetal movements from the middle of the month. At the end of the month the length of 20 cm, the weight is 300 g.
Growth of the baby, 6th month of pregnancy.
In the sixth month eyebrows and eyelashes are formed, nails begin to grow, and at the end of the month the hair on the head. The length is 30 cm, the weight is 600-700 g. The enlargement of the uterus has reached about the height of the maternal navel.
Growth of the baby, 7th and 8th months of pregnancy.
At the end of the seventh month the length of 30 cm, the weight is 800-1000 g.At the end of the eighth month, you can observe a length of 40 cm and a weight of 1500-1700 g.
Growth of the baby, 9th and 10th month of pregnancy.
In the ninth month of pregnancy, there is a stronger formation of the fat pad and thus the rounding of the body shapes. The woolly coat is shed again. The child is 45 cm long, its weight is 2000-2500 g. At the end of the 10th month of pregnancy, the mature child is born, which should then have a length of 50 cm and a weight of 3000-3500 g. We hope that this small insight into the development of your baby in the womb was informative. We recommend the following further reading books for this purpose:
