Intrauterine development of the fetus
All the nutrients necessary for its development, the fetus receives from the mother's body. At the beginning of pregnancy, these substances enter the fetal egg through the villi covering it. In the future this process takes place through a child's place. It begins to develop at about 3 months of pregnancy as a result of the growth of villi that side of the fetus that is lodged with the uterine wall. As the period of pregnancy and development of the fetus increase, the development of a child's place also takes place. By the end of pregnancy, it is a fleshy lobed formation, whose weight reaches about 500 grams. The connection between the fetus and the uterus is through the child's place and the umbilical cord, which, as it were, connects the fetus with the child's place. Inside the umbilical cord, which looks like a cord( by the end of pregnancy, the umbilical cord reaches 50 centimeters or more), blood vessels pass through which blood flows from the child's place to the fetus and from the fetus to the child's place. In this way, the fetus is provided with the opportunity to receive from the mother's organism all that is necessary for its development and, in turn, to remove the waste substances through the umbilical cord and the child's place.
Nutrients, before they enter the fetus from the mother's body, are subjected to a number of changes in the child's place, as a result of which they become suitable for the perception of their fetus. This is a very complex process in which the child's place plays for the fetus, as it were, the role of the organ of respiration, nutrition and excretion. For a woman, a child's place is a new one, which has arisen only during pregnancy with the gland of internal secretion.
Fetus, umbilical cord and child's place( diagram).
It is clear that the development of the fetus depends largely on the state of the woman's health, on the conditions of her life, the characteristics of nutrition, the observance of hygienic rules.
During fetal life the fetus grows rapidly and develops. In the first 8 weeks( from the time of fertilization), the embryo is formed. By the end of the second month, it resembles the appearance of a person and it is possible to distinguish between the head, trunk and limbs. From now on, it is called a fruit. Various diseases of the mother, especially infectious, malnutrition, violation of the hygienic regime( overheating, hard work, overwork, etc.) adversely affect the fetus, can lead to a slowed or incorrect development of it, cause its inferiority and even death.
Previously it was believed that the fetus is completely protected from external influences by the placental barrier. Now it is known that through the placenta many microorganisms and toxins, as well as many chemical preparations, come to the fetus. Especially dangerous for the fruit is alcohol. He is quickly absorbed into the mother's blood, enters the fetus and can be found in his blood. The same applies to nicotine.
Some medicinal substances, especially taken by pregnant women in significant doses for a long period, are not indifferent to the fetus. Often, pregnant women use various medicines without prescribing a doctor.
Among part of the population, there is an opinion that the condition of the mother in the second half of pregnancy is especially important for the fetus. This opinion is erroneous. Scientific researches established that the sensitivity of the fetus to the influence of harmful factors is especially increased in the early terms of its development. The first 2 months of pregnancy are the critical period during which, under the influence of various adverse effects, most often there are disorders in the development of the embryo.
By the end of 3 months of pregnancy the fetus reaches 8-9 centimeters, by the end of the IV month, 15-16 centimeters, and a month later - about 25 centimeters. For each subsequent month, the fetus increases by an average of 5 centimeters.
The increase in fetal weight occurs less evenly than the increase in growth. So, by the end of the third month, it usually weighs 40-50 grams, by the end of the fourth month - 120 grams. During the following month its weight increases several times, reaching 220-230 grams. At the end of the sixth month the weight of the fetus is close to 700 grams. Especially large growth and weight reaches the fetus in the last 3 months of pregnancy.
At the end of the VII month of pregnancy( ie, at 28 weeks), the fruit reaches 35 centimeters, and its weight at that time exceeds one kilogram. This term is in some respects borderline: abortion of pregnancy earlier 7 months is called as a miscarriage, and later this term - premature birth.
Born at 30-32 weeks of pregnancy, the child weakly screams, swallows badly, does not "take" immediately the mother's breast, but is still viable. When creating favorable conditions for these children often manage to go out. With premature births at a later date, the possibility of nursing a child is significantly increased.
It is a common opinion among the population that with a 7-month premature birth the child survives, and with 8-month-old deaths, is not based on anything and is erroneous.
By the end of pregnancy the fruit reaches usually 49-50 centimeters, its weight more often exceeds 3 kilograms. Often full-term babies are born with a smaller weight of and growth, and sometimes with significantly greater.
Too much growth and especially the weight of the fetus( more than 4000 grams) are often observed with a sedentary lifestyle of pregnant and malnutrition with excessive intake of food, also with certain diseases of the mother( diabetes, etc.).The development of a very large fetus increases the possibility of complications in childbirth.
/ The fetus located in the uterus is surrounded by shells that make up a bag, inside of which is a special fluid - amniotic fluid. This structure of the fetal egg protects the fetus from external injuries and from the introduction into it of infection from the vagina.
The presence of amniotic fluid allows the fetus to produce movements. They usually begin with the third month of pregnancy, but the woman feels them later: the first-pregnancy senses these fetal movements usually in the middle of pregnancy, ie, by 20 weeks, and women who have already given birth begin to feel
weeks earlier,e. in 18 weeks of pregnancy. Intrauterine movements of the fetus are sometimes not clearly expressed, so not all women feel them for the first time at the same time of pregnancy. By the end of pregnancy, fetal movements become more rare.
From the middle of pregnancy, you can listen to the heartbeat of the fetus. This is the most accurate sign of pregnancy. Palpitation of the fetus at the end of pregnancy in frequency exceeds the heartbeat of an adult almost 2 times and is equal to 120-130 beats per minute.
The fetus can change its position in the uterus during movements until about 8 months of pregnancy. In later terms, this is observed less often, and before the very birth( with full term pregnancy) - extremely rare.
By the end of pregnancy, the fetus lies in the uterus in the longitudinal position, i.e., respectively, the length of the uterus. This position of the fetus is found in 99.5% of cases and is correct. The head of the fetus is usually located at the bottom - at the entrance to the pelvis of the mother, and the buttocks of the fetus - in the bottom of the uterus.
Finding the head of the fetus at the bottom of the uterus is due primarily to the fact that the head is the heaviest part of the fetal body. In addition, the head is the most bulky part of the fruit. During childbirth, it first passes through the birth canal of the mother, and this is a favorable factor for both the mother and the fetus.
In some cases, there is a transverse or oblique position of the fetus, at which the birth can not occur on its own. These provisions should be corrected, i.e. the fetus must be transferred to the longitudinal position, which requires special medical care at the end of pregnancy or already in labor.