The placenta forms in the earliest gestational age (from 2–3 weeks). At this time, the emerging cells are divided into two types – embryoblast (germ) and trophoblast. All systems and organs of the embryo will develop from the first; from the second, extra-embryonic organs and tissues — the chorion, the yolk sac, the amnion.
From the chorionic villi, the same organ is formed, which is called the placenta. The villi come in contact with the maternal blood, thanks to which the embryo receives from the mother the nutrients it needs, oxygen and releases waste products and carbon dioxide. From the third week of development, the placenta produces hormones that are necessary for the development of the future man.
Alas, the early placenta can not protect the future baby. Therefore, gross defects, chromosomal and genetic damage can develop, and the embryo – to die.
In the second trimester (13–20 weeks), the weight of the placenta increases by 10 g. At 16 weeks the weight of the embryo and placenta is about the same, after which the future baby gradually becomes heavier than the placenta. By the end of the 20th week of pregnancy, the placenta is fully formed: it has a lobular structure and mature villi. To all its functions, one more is added – protective.
From now on, she will protect the baby from the harmful effects.
Starting from the 30th week with an ultrasound examination, the doctor will necessarily evaluate the structure of the placenta. The future mother will hear words such as the degree of maturity of the placenta.
Structural changes occur in parallel with the growth and development of the child. From the 30th to the 40th week, the placenta gradually matures from zero to third degree. The discrepancy between the degree of maturity and the term of a child may be due to pregnancy complications: placental insufficiency, preeclampsia, etc. Alas, this organ cannot be rejuvenated.
In such a situation, the main thing is to monitor the state and development of the child, that is, with the help of CTG, ultrasound, dopplerometry, in dynamics, to evaluate the parameters of the baby and the blood flow in the placenta. If everything is within normal limits – the placenta is in working condition.
As for medicines, there is no convincing evidence of their effectiveness in such a situation.
When the placenta does not cope with its functions and the child suffers from a lack of oxygen and nutrients, doctors talk about placental insufficiency. It may be chronic or occur suddenly, for example, when placental abruption takes place.
The risk group consists of future mothers over 35, women who smoke and take a great interest in alcohol, future mothers with chronic somatic diseases such as diabetes, cardiovascular diseases, kidney diseases, etc. The risk may also increase due to problems in the female genital area uterine fibroids, genital infantilism, menstrual disorders, inflammation of the genitals. Every time the doctor seeks the answer to the question: is it true placental insufficiency or is it just that in this family all children are born small and underweight.
Placental insufficiency may manifest as intrauterine growth retardation and / or fetal hypoxia. In order to detect the problem in time, each time the obstetrician-gynecologist visits all expectant mothers, the height of the uterus floor and the abdominal circumference are measured, the nature of the child’s movement is assessed.
If the size of the uterus does not correspond to the gestation period, an ultrasound examination is carried out and every 2-3 weeks ultrasound monitors the growth and development of the baby, as well as cardiotocography and Doppler study. With the help of the first, the condition of the future little man is assessed according to the nature of his heart contractions, and with the help of the second, the intensity of blood flow is judged both in the uterine and umbilical arteries and in the child’s vessels.
The dividing egg is implanted, that is, attached inside the uterus, on the 7th day after fertilization. And in the same place the placenta is formed.
If there are inflammations in the uterus, myomatous nodes, scars, the placenta may attach too low (in the area of the isthmus or internal pharynx). Then they talk about low placentation and / or placenta previa. This means that it is located on the way in which the child will move to the exit to the light.
However, the diagnosis of placenta previa is valid only in the third trimester. Until that time, we can only talk about its low location. Why?
In the first half of pregnancy, the placenta grows faster than the uterus. In the second – the picture changes, the muscular layers of the uterus stretch, and the placenta can rise up a few centimeters. So the previa is, fortunately, rare.
But such a complication of pregnancy is very dangerous for both women and children. The main symptom is a sudden bleeding from the genital tract, which can be repeated. And the closer to childbirth, the more often.
The fact is that at the end of pregnancy the muscle fibers in the lower parts of the uterus begin to periodically contract, and the placenta does not have this ability.
Therefore, it can flake off, leading to bleeding. Due to the high risk of serious complications during childbirth in placental abruption, doctors urgently, regardless of the gestational age, give the woman a cesarean section.