Every woman who dreams of adding to her family, seeing the long-awaited two lines on the test, becomes indescribably delighted. Literally from the first days of pregnancy, she begins to show concern for the unborn baby: she refuses bad habits, follows a diet, reduces physical exercise. However, not all ladies delve into the intricacies of the development of a tiny organism, limiting themselves to only studying ultrasound images. Meanwhile, while in the womb, the embryo goes through a long journey before turning into a full-fledged little person. In this article we will look at the difference between a fetus and an embryo.

Definitions

Fetus- developing in the mother's womb human body after the laying of the main systems and organs. This term is used exclusively in relation to an unborn child. The period of development of the body under consideration is called fetal and begins when it reaches 8-9 weeks of age. This stage is characterized by intensive growth, tissue differentiation, development of organs and systems, and the completion of the formation of the fetal membranes and placenta. A 38-week baby is considered fully term. At this point, the fetus acquires signs of maturity: length from 47 cm, weight from 2500 g, convex breasts, pale pink skin without wrinkles, etc. Babies born between 28 and 37 weeks are considered premature, but at the same time quite viable. They require very careful care and are sometimes under the supervision of doctors for a long time. The most effective method Ultrasound examination is recognized for fetal diagnostics.

Embryo– a human embryo at the initial stage of its development until it emerges from the membranes. During this stage, a body is formed from the egg, which has certain morphological characteristics. This period lasts 8 weeks, after which the embryo is usually called a fetus. The embryo results from the fusion of the nuclei of the egg with the sperm. At the end of the third week of development, the embryo develops a head and a primitive heart, and after a few more days it begins to pump blood throughout the body and placenta. During the formation of the embryo, limbs and eyes, ears and the beginnings of teeth are formed, the tail gradually decreases, and then completely disappears. By the end of the eighth week, the process of laying the main vital organs is almost complete.

Comparison

Both of these terms refer to a growing organism at different stages of development. An embryo is a fetus from the moment of conception until the 8th week of pregnancy. A microscopic body appears in the fertilized egg, which is an oval or round formation several millimeters in size. The yolk sac inside provides nutrition to the embryo. The fertilized egg increases in size along with the embryo. At the initial stage of formation, the embryo bears little resemblance to a human being. It looks like a tiny crooked “worm” with a tail and no clearly defined head. Closer to 8-9 weeks, the embryo develops limbs, eyes, the heart begins to beat, and other vital organs are formed. The head becomes visible, but disproportionately large in relation to the body. The maximum size of the embryo reaches only 3-4 cm, and its weight is about 5 g.

The main difference between a fetus and an embryo is the intrauterine age of development. As mentioned above, the embryo is the organism that forms during the first eight weeks. Upon reaching this age, the embryo begins to be called a fetus. From now on, its nutrition is provided not by the yolk sac, but by the placenta, an organ located inside the uterus that communicates between the mother and the unborn baby. As he develops, he becomes more and more human-like. The body lengthens and acquires normal proportions, the limbs increase in size, the ears take their place on the sides of the head, etc. The fetus is actively growing and gaining weight. The weight of a full-term toddler is at least 2.5 kg, and the height is 47 cm.

Let's summarize what is the difference between a fetus and an embryo.

In fact, this topic is very relevant in many women's forums, and future, as well as real mothers, are passionately discussing what period is considered normal for the birth of a child. Today we want to tell you the opinion of official medicine. Let’s make a reservation right away: despite clear data on what week a baby is considered full-term, there are exceptions to this rule. Moreover, the birth of a baby a little earlier or later than the average term almost never threatens his life and health. However, doctors will try to stop the onset of labor much earlier than expected and delay the time as much as possible.

Delivery on time

The ideal time for the baby to appear is the fortieth week. It was by this time that he managed not only to completely complete the formation of internal organs, but also to build up a sufficient amount of subcutaneous fat for effective thermoregulation. Therefore, speaking about what week a baby is considered full-term, it seems logical to say 40 weeks. The child is completely ready to be born and live outside the mother’s tummy, and there should be no fears for his life and health. However, not all babies are born at exactly 40 weeks. According to statistics, only 9% of women give birth exactly at 40 weeks.

Standard options

It is precisely because of the high variability that obstetricians-gynecologists and pediatricians have somewhat reconsidered the question of at what week a child is considered full-term. What can be considered normal or at least acceptable for childbirth? This is a fairly long period of time from the 37th to the 42nd week inclusive. However, the terminology is slightly different. Childbirth before the 37th week (the 36th is no exception) is considered premature, and babies born at this time are considered premature. From the 37th to the 40th week, the optimal period for the birth of babies begins, therefore, during this period, childbirth is called physiological. Finally, starting with it is considered post-term, and by the end of the 42nd week, doctors will send the woman to the maternity hospital to stimulate labor. We have already answered the main question, from what week the baby is considered full-term, but there are still a number of points that need to be discussed.

Woman at 37 weeks

You can be congratulated, the long journey of experiences is almost behind you. This is especially true for those whose pregnancy proceeded with the threat of miscarriage. Now you know exactly after what week the baby is considered full-term. Starting from the 37th week, the whole family should be prepared for the fact that the baby could be born at any moment. The remaining time will not play a role in the development of the baby, but he will be able to grow a little and accumulate subcutaneous fat, which is important for maintaining heat in a small body. At this time, some pregnant women are very balanced, while others, on the contrary, feel increasing anxiety before the upcoming birth. The cervix begins to slowly dilate, as soon as it is ready, it will recede, which until now has protected the uterus from infections. This usually happens a few hours or days before birth.

Symptoms of approaching labor

Even knowing from what moment the baby is considered full-term, a woman sometimes gets a little lost when she feels. Moreover, the better you imagine exactly what they should be like and how to behave when they appear, the less time there will be for panic.

However, let’s make one more digression; it concerns packing things for the maternity hospital. Knowing at what stage a pregnancy is considered full-term, you need to start preparing in advance. You need to buy a discharge kit, diapers and undershirts for the maternity hospital, collect a bag of personal belongings and put a separate discharge kit for yourself. Believe me, this is much better than trying to find a robe or other toiletries in the closet as contractions progress.

During this period, most women begin to experience insomnia. A big belly and the baby’s active life do not contribute to the mother’s sound sleep. However, it won't be long until he appears, so try to enjoy these last moments. Frequent urination may bother you, which can also be easily explained by the fact that a large fetus puts pressure on internal organs. It is during this period that leg cramps often first appear. Be sure to monitor your vaginal discharge. Usually in the last week they become a little more abundant and lighter. And if you noticed significant amount clear mucus on your underwear, which means labor is very close.

Indirect signs

It must be said that they are not found in all women, in addition, some note only some of them. However, in any case, you have no reason to worry. You already know which baby is considered full-term; the 37th week has passed, which means that whenever labor begins, he will be born completely ready for it. Remember this every day, so that sudden labor activity is not a reason for panic, but, on the contrary, a long-awaited event.

Diarrhea can warn you that labor is approaching. This is a normal physiological reaction that allows a woman in labor to cleanse her intestines. If this does not happen, it is recommended to cleanse yourself using an enema. It is no longer mandatory to do it in the hospital, but before calling an ambulance, you can easily do it yourself. Very often, just before giving birth, women experience a burst of activity. Suddenly you want to clean the windows and wash the curtains, wash the whole house right down to the entrance. It is our instincts that tell us that we need to prepare a nest in which a baby will soon appear.

Contractions and the onset of labor

You have already experienced them before, but if previously they were short-lived and went away if you stood up and moved a little, now the situation changes. Often the mucus plug comes off first, then and finally contractions begin. It also happens the other way around: the first symptoms are contractions. In this case, the main thing is not to panic. Double-check the bag you take to the hospital. Place your passport and exchange card nearby. Consider breathing exercises that will help relieve pain during labor and childbirth. You shouldn’t go to bed right away, walk around the house, you can even go outside and get some air. This will only intensify real contractions, and you will be sure that it is time to call an ambulance.

Memo for the expectant mother

The delivery room is not a place for panic, so even during pregnancy, mentally scroll through the whole picture of the events taking place several times in your head. Again, ask your doctor the question from what week is the pregnancy considered full-term. He will tell you that the lower limit of normal is 37-38 weeks. This means that from about this time you need to prepare yourself mentally. Close your eyes and imagine that contractions are starting, at the same time remember the breathing exercises during contractions, how you calmly get ready, go to the hospital and give birth to a healthy baby. This attitude will greatly help you overcome anxiety.

In accordance with Art. 17 of the Civil Code of the Russian Federation, the legal capacity of a citizen (the ability to have civil rights and duties) arises at the moment of his birth. It is likely that the moment of birth of a citizen is understood as the moment of separation of the fetus from the mother’s body and the beginning of its autonomous existence. Thus, the law does not recognize a human fetus as having legal capacity, regardless of its age, that is, it does not give it the status of a subject.

Some lawyers associate the emergence of legal capacity with the act of registering a birth, pointing out: “If the intrauterine development of the child was less than six months, then legal capacity does not arise, since neither the fact of birth nor the fact of death is registered. A similar conclusion can be drawn if intrauterine development was more than six months, but the child lived for several minutes after birth, since in in this case only a death certificate is issued." A more convincing position seems to be that "from the point of view of law, it does not matter whether the child was viable: the very fact of his birth means that he acquired legal capacity, even if he was only alive a few minutes or even seconds."

Some lawyers believe that “the determination of the moment of birth and death is not the subject of legal science, since we are talking about purely physiological concepts. For law, it is only important that from the moment when a citizen is considered born, and medicine, as a rule, is guided in this case by the criterion the beginning of independent breathing, the child acquires civil legal capacity."

In accordance with Art. 36 of the Fundamentals of the Legislation of the Russian Federation on the protection of the health of citizens, a woman’s rights to artificial termination of pregnancy are limited when the pregnancy is over 12 weeks, and for social reasons - when the pregnancy is over 22 weeks. This position of the legislator indicates that he treats the intrauterine fetus from a certain period of its development not just as a physiological part female body, which she disposes of independently, but as a special kind of being with the right to life. It is this right that is protected by recognizing the illegality of abortion after reaching a certain period of fetal development. The right, in accordance with legal doctrine, can belong only to the subject.

Taking into account the above, I believe that the beginning of life should be considered not the moment of human birth, but the achievement by the intrauterine fetus of a certain stage of development, while the fetus that has reached a certain level of development should be recognized as a human being, possessing special legal personality and provided with civil legal protection.

This point of view is also supported by representatives of the science of criminal law, according to whom, the current state of law “violates the rights of the fetus to life and health, and criminal law is obliged to protect its rights. The object of murder is formed public relations ensuring the safety of citizens' lives. The life of any person is subject to criminal legal protection, regardless of his age, physical and moral qualities from the beginning of birth until the moment of death. The beginning of human life should be understood as the beginning of physiological childbirth. The destruction of a child's fetus before the birth process begins does not constitute murder. The moment of end of life should be considered biological death, in which the activity of the central nervous system ceases. nervous system and in the cerebral cortex, an irreversible breakdown of protein bodies occurs, as a result of which it is no longer possible to restore the vital functions of the body. Commentary to Art. 105 of the Criminal Code of the Russian Federation.

The development of the human embryo is one of the most interesting phenomena in biology and medicine. From just two cells within 9 months it arises new life- the child that his parents had been waiting for and wishing for. How does the development of the embryo and fetus occur?

Stages of embryo development

Strictly speaking, an embryo is a human embryo from fertilization to the 10th obstetric week. From the 10th week, the embryo is considered a fetus, and the further period is called fetal (from the Latin fetus - fruit). Before this period, the development of the embryo by day (from the moment of fertilization) takes 49 days.

The first trimester of pregnancy is the most difficult and critical. During this period, all harmful influences can lead to disruptions in the development process and the formation of organs and systems of the unborn baby. Let's find out what stages of embryo development have been identified by scientists.

Stages of embryo development

Immediately after fertilization of the egg, the genetic material of the mother and father merges, forming a new, completely unique set of genes. In addition, the synthesis of substances necessary for further growth is launched.

Approximately 30 hours after fertilization, the first division occurs. 2 cells are formed, then 4, 8, 16 and so on. The embryo does not increase in size much as the number of cells increases. When a certain number of cells is reached, the rate of division slows down. At this point the embryo is called a morula.

Morula cells begin to migrate to the periphery, resulting in the formation of a cavity in the center of the embryo. This stage of development is called blastula. At this stage of development, it is possible for the blastula to separate to form identical twins. The blastula contains several hundred cells.

In the future, the skin, nervous system, and eyes are formed from the ectoderm.

From the mesoderm - bones, muscles, blood vessels, kidneys.

From the endoderm - the gastrointestinal tract, respiratory system.

At this stage the embryo is called a gastrula. This happens 8-9 days after fertilization. Around this time, implantation occurs - the implantation of the embryo into the uterine mucosa.

Embryo development (photo by Lennart Nilsson). Embryo on the lining of the uterus:

Embryo with heart bud:

The next stage, called neurula, begins the formation of the nervous system. During this period, failures are possible that will lead to severe pathology of the fetus. The reason is most often banal - a cold, medication or lack of vitamins and minerals. This is why it is important to eat right in the first months of pregnancy and avoid stress and colds.

Organogenesis - laying down of organs

Further development of the embryo occurs with the formation of vital organs. On day 20, the rudiment of blood vessels and the baby’s heart is formed. It will make its first contraction between 22 and 28 days after fertilization and will not stop until the very end of life. During the same period, the lungs, ears, mouth, and spinal cord are formed. The spleen appears. By the way, during this period we all had tails.

By the end of the first month, the embryo has the rudiments of eyes, small arms and legs. The buds are being laid.

One and a half months after fertilization, the fetal heartbeat can be heard during an ultrasound. The embryo begins to make spontaneous movements. During this period, almost all vital organs are already formed.

With the beginning of the second trimester, unpleasant phenomena for the mother, in the form of attacks of nausea, heightened perception of smells, and the frequent need to visit the restroom, cease. However, you should pay a visit to the doctor, do the necessary tests and, of course, an ultrasound to determine the sex of the child.

Further development of the fetus occurs with weight and height gain. Before giving birth, the baby should recover up to 3 kg and grow to about 50 cm. While doing this, he will suck his finger, cry silently, kick and shove quite noticeably, and sleep.

Despite the fact that all organs are already in place, their activity is low. The lungs are folded like a parachute. They will have to open up with the first breath. The liver and kidneys are still idle. Their function is almost entirely performed by the mother's body.

Only the baby’s heart works at 200%. The normal heart rate for babies in the womb is between 120 and 160 beats per minute. At the same time, “cosmetic” changes occur. Marigolds, eyelashes, eyebrows, and fluff appear on the skin. The baby is preparing for birth.

How is the gestational age calculated?

The development of the embryo by week, from the date of the last menstruation to birth, is counted in obstetric weeks. From real time pregnancy, from the moment of fertilization, the obstetric period differs by 2-3 weeks, since on average 14 days pass from the moment of the last menstruation to the moment of fertilization. Therefore, a normal pregnancy of 40 obstetric weeks is equal to 38 weeks from the moment of fertilization.

The birth of a child is a real miracle. But miracles must be treated very carefully. Be sure to visit your doctor regularly and get the necessary tests. Protect yourself from colds and dress according to the season. Do not engage in active sports. Smile more often. After all, you will soon be a mother.

"The hero is born!" - hears a young mother whose newborn weighs more than 4 kilograms. Many parents are convinced that a large child is good: if he weighs a lot, it means he is strong and healthy. Unfortunately, this widespread opinion is not always justified - the birth of a child with a large weight is sometimes associated with some problems.

First, let's define the terms. If the baby's weight at birth is 4000-5000 g, the fetus is considered large. With a weight of 5000 g and above, the fruit is called giant. In this case, the child’s height is not taken into account, although, as a rule, the body length of such a “hero” also exceeds the statistical average. So, if the fetal “height” of 48-54 cm is considered normal, then in large children this figure can be 54-56 cm. It should be noted that in last years there is an increase in average weight, height and physical development newborns. This is probably due to improved working, living and nutritional conditions for pregnant women. According to research, the number of newborns with a birth weight of 4000 g and above is 5-10%. The birth of giant children is much less common.

Why is the baby so big?

Risk factors for having large children are: heredity, diabetes, some other endocrine diseases, increased duration of pregnancy, etc.

Increased pregnancy duration can lead to the birth of large children. In this case, both prolongation of physiological pregnancy and true post-maturity are possible.

Prolonged pregnancy is considered to be one that lasts longer than the physiological one by 10-14 days and ends with the birth of a functionally mature child without signs of post-maturity and “aging” of the placenta.