The placenta is the organ that allows you to bear a child in the womb. It supplies the fetus with useful substances, protects it from the internal environment of the mother's body, produces hormones necessary to maintain pregnancy and many other functions that we can only guess about.
Formation of the placenta
The formation of the placenta begins from the moment the fertilized egg attaches to the wall of the uterus. The endometrium grows together with the fertilized egg, tightly fixing it to the wall of the uterus. In the place of contact between the zygote and the mucosa, the placenta grows over time. The so-called placentation begins from the third week of pregnancy. Until the sixth week, the embryonic membrane is called the chorion.
Until the twelfth week, the placenta does not have a clear histological and anatomical structure, but after, until the middle of the third trimester, it looks like a disc attached to the wall of the uterus. From the outside, the umbilical cord extends from it to the child, and the inside is a surface with villi that swim in the mother's blood.
Functions of the placenta
Children's place forms a connection between the fetus and the mother's body through the exchange of blood. This is called the hematoplacental barrier. Morphologically, it is a young vessel with a thin wall, which form small villi over the entire surface of the placenta. They come into contact with the gaps located in the wall of the uterus, and blood circulates between them. This mechanism provides all the functions of the organ:
- Gas exchange. Oxygen from the mother's bloodstream enters the fetus, and carbon dioxide is transported back.
- Nutrition and excretion. It is through the placenta that the child receives all the substances necessary for growth and development: water, vitamins, minerals, electrolytes. And after the body of the fetus metabolizes them into urea, creatinine and other compounds, the placenta utilizes everything.
- Hormonal function. The placenta secretes hormones that help maintain pregnancy: progesterone, human chorionic gonadotropin, prolactin. In the early stages, this role is taken over by the corpus luteum, located in the ovary.
- Protection. The hematoplacental barrier does not allow antigens from the mother's blood to enter the child's blood, in addition, the placenta does not allow many drugs, its own immune cells and circulating immune complexes to pass through. However, it is permeable to drugs, alcohol, nicotine and viruses.
Degrees of maturity of the placenta
The degree of maturation of the placenta depends on the duration of the woman's pregnancy. This organ grows with the fetus and dies after birth. There are four degrees of placental maturity:
- Zero - in the normal course of pregnancy lasts up to seven lunar months. It is relatively thin, constantly growing and forming new gaps.
- First - corresponds to the eighth gestational month. The growth of the placenta stops, it becomes thicker. This is one of the critical periods in the life of the placenta, and even a minor intervention can provoke an abruption.
- Second - continues until the end of pregnancy. The placenta is already beginning to age, after nine months of hard work, it is ready to leave the uterine cavity after the baby.
- Third - can be observed from the thirty-seventh week of gestation inclusive. This is the natural aging of an organ that has fulfilled its function.
Placenta Attachment
Most often the placenta is located on the back wall of the uterus or goes to the side wall. But it is finally possible to find out only when two-thirds of the pregnancy is already over. This is due to the fact that the uterus increases in size and changes its shape, and the placenta moves with it.
Usually, during the current ultrasound examination, the doctor notes the location of the placenta and the height of its attachment relative to the uterine os. Normally, the placenta on the back wall is high. At least seven centimeters should be between the internal os and the edge of the placenta by the third trimester. Sometimes she even crawls to the bottom of the uterus. Although experts believe that such an arrangement is also not a guarantee of successful delivery. If this figure is lower, then obstetrician-gynecologists speak of a lowlocation of the placenta. If there are tissues of the placenta in the throat area, then this indicates its presentation.
There are three types of presentation:
- Complete when the internal os is blocked by the placenta. So in case of premature detachment, there will be massive bleeding, which will lead to the death of the fetus.
- Partial presentation means that the pharynx is blocked by no more than a third.
- Marginal presentation is established when the edge of the placenta reaches the throat, but does not go beyond it. This is the most favorable outcome of events.
Periods of childbirth
Normal physiological childbirth begins at the time of the appearance of regular contractions with equal intervals between them. In obstetrics, there are three periods of childbirth.
The first period is the opening of the cervix. The birth canal must be prepared for the fact that the fetus will move along it. They should expand, become more elastic and softer. At the beginning of the first period, the opening of the cervix is only two centimeters, or one obstetrician's finger, and by the end it should reach ten or even twelve centimeters and skip a whole fist. Only in this case the baby's head can be born. Most often, at the end of the disclosure period, amniotic fluid is poured out. In total, the first stage lasts from nine to twelve hours.
The second period is called the expulsion of the fetus. The contractions are replaced by attempts, the bottom of the uterus contracts intensely and pushes the baby out. The fetus moves through the birth canal, turning according to the anatomical features of the pelvis. ATdepending on the presentation, the baby may be born head or buttocks, but the obstetrician must be able to help him be born in any position.
The third period is called the afterbirth and begins from the moment the child is born, and ends with the appearance of the placenta. Normally, it lasts half an hour, and after fifteen minutes the placenta separates from the wall of the uterus and is pushed out of the womb with the last attempt.
Delayed placenta separation
The causes of retention of the placenta in the uterine cavity may be its hypotension, placenta accreta, anomalies in the structure or location of the placenta, fusion of the placenta with the wall of the uterus. Risk factors in this case are inflammatory diseases of the uterine mucosa, the presence of scars from caesarean section, fibroids, and a history of miscarriages.
A symptom of retained placenta is bleeding during and after the third stage of labor. Sometimes the blood does not immediately flow out, but accumulates in the uterine cavity. Such occult bleeding can lead to hemorrhagic shock.
Placental accreta
A placenta accreta is called its tight attachment to the wall of the uterus. The placenta can lie on the mucosa, be immersed in the wall of the uterus to the muscle layer and grow through all layers, even affecting the peritoneum.
Manual separation of the placenta is possible only in the case of the first degree of increment, that is, when it is tightly adherent to the mucosa. But if the increment has reached the second or third degree, then surgical intervention is required. As a rule, ultrasound can distinguish how the baby's place is attached towall of the uterus, and discuss this point in advance with the expectant mother. If the doctor finds out about such an anomaly in the location of the placenta during childbirth, then he must decide to remove the uterus.
Methods of manual separation of the placenta
There are several ways to perform manual separation of the placenta. These can be manipulations on the surface of the mother's abdomen, when the afterbirth is squeezed out of the uterine cavity, and in some cases, doctors are forced to literally take out the placenta with membranes with their hands.
The most common is Abuladze's technique, when an obstetrician gently massages the woman's anterior abdominal wall with his fingers, and then invites her to push. At this moment, he himself holds his stomach in the form of a longitudinal fold. So the pressure inside the uterine cavity increases, and there is a chance that the placenta will be born by itself. In addition, the puerperal catheterizes the bladder, which stimulates the contraction of the muscles of the uterus. Oxytocin is given intravenously to induce labor.
If manual separation of the placenta through the anterior abdominal wall is ineffective, then the obstetrician resorts to internal separation.
The placenta separation technique
The technique of manual separation of the placenta is removing it from the uterine cavity in pieces. An obstetrician in a sterile glove inserts his hand into the uterus. At the same time, the fingers are maximally brought to each other and extended. To the touch, she reaches the placenta and carefully, with light chopping movements, separatesher from the wall of the womb. Manual removal of the afterbirth must be very careful not to cut through the wall of the uterus and cause massive bleeding. The doctor gives a sign to the assistant to pull the umbilical cord and pull out the child's place and check it for integrity. The midwife, meanwhile, continues to feel the walls of the uterus to remove any excess tissue and make sure that there are no pieces of the placenta left inside, as this can provoke a postpartum infection.
Manual separation of the placenta also involves uterine massage, when one hand of the doctor is inside, and the other gently presses on the outside. This stimulates the receptors of the uterus, and it contracts. The procedure is performed under general or local anesthesia under aseptic conditions.
Complication and consequences
Complications include bleeding in the postpartum period and hemorrhagic shock associated with massive blood loss from the vessels of the placenta. In addition, manual removal of the placenta can be dangerous with perforation of the uterus and the development of postpartum endometritis or sepsis. Under the most unfavorable circumstances, a woman risks not only her he alth and the possibility of having children in the future, but also her life.
Prevention
In order to avoid problems in childbirth, you need to properly prepare your body for pregnancy. First of all, the appearance of a child should be planned, because abortions violate the structure of the endometrium to some extent, which leads to a dense attachment of the child's place in subsequent pregnancies. Needs to be diagnosed and treated promptlydiseases of the genitourinary system, as they can affect reproductive function.
It is recommended to exclude casual sex without the use of barrier methods of contraception, maintain personal hygiene and maintain the immune system in the autumn-spring period.
Timely registration for pregnancy plays a big role. The sooner the better for the child. Doctors obstetricians and gynecologists insist on regular visits to the antenatal clinic during the period of gestation. Be sure to follow the recommendations, walking, proper nutrition, he althy sleep and exercise, as well as the rejection of bad habits.
