The placenta is an organ that allows you to carry a baby in the womb. It supplies the fetus with beneficial substances, protects it from the internal environment of the mother’s body , produces hormones necessary to maintain pregnancy and many more functions that we can only guess about.
Placenta formation
The formation of the placenta begins from the moment the fetal egg attaches to the uterine wall. The endometrium fuses with a fertilized egg, tightly fixing it to the wall of the uterus. In the place of contact of the zygote and mucous membrane, the placenta grows over time. The so-called placentation begins already from the third week of pregnancy. Until the sixth week, the germinal membrane is called 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 disk attached to the wall of the uterus. An umbilical cord extends from the outside to the baby, and the inside is a surface with villi that float in the mother’s blood.
Placenta function
A child'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 represents young vessels with a thin wall that form small villi over the entire surface of the placenta. They come in contact with the gaps located in the wall of the uterus, and blood circulates between them. This mechanism provides all the functions of an organ:
- Gas exchange. Oxygen with the blood flow of the mother 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 the growth and development: water, vitamins, minerals, electrolytes. And after the fetal body metabolizes them into urea, creatinine and other compounds, the placenta utilizes everything.
- Hormonal function. The placenta secretes hormones that help maintain pregnancy: progesterone, chorionic gonadotropin, prolactin. In the early stages, the corpus luteum located in the ovary takes on this role.
- Protection. The hematoplacental barrier does not allow antigens from the mother’s blood to enter the baby’s blood, in addition, the placenta does not pass many drugs, its own immune cells and circulating immune complexes. However, it is permeable to drugs, alcohol, nicotine and viruses.
Placental maturity
The degree of maturation of the placenta depends on the gestational age of the woman. This organ grows with the fetus and dies after its birth. Four degrees of placental maturity are distinguished:
- Zero - in the normal course of pregnancy, it lasts up to seven lunar months. It is relatively thin, constantly increasing and forming new gaps.
- The 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 minor intervention can provoke detachment.
- The second - continues until the end of pregnancy. The placenta is already starting to age, after nine months of hard work, she is ready to leave the uterine cavity after the baby.
- The 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 posterior wall of the uterus or passes to the side wall. But it is finally possible to find out only when two-thirds of the pregnancy is already behind. 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 pharynx. Normally, the placenta on the back wall is high. At least seven centimeters should be between the internal pharynx 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 say low placenta. If placenta tissue is present in the throat area, then this indicates its presentation.
There are three types of presentation:
- Complete when the internal pharynx is blocked by the placenta. So in the case of its premature detachment there will be massive bleeding, which will entail the death of the fetus.
- Partial presentation means that the pharynx is blocked by no more than a third.
- Regional presentation is established when the edge of the placenta reaches the pharynx, but does not go beyond it. This is the most favorable outcome of events.
Birth periods
Normal physiological birth 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 should be prepared for the fact that the fetus will move along them. 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 finger of an obstetrician, and by the end it should reach ten, or even twelve centimeters, and miss a whole fist. Only in this case the baby’s head will be able to 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. Contractions are replaced by attempts, the bottom of the uterus is intensively reduced and pushes the baby out. The fetus moves through the birth canal, turning according to the anatomical features of the pelvis. Depending on the presentation, the child may be born with his head or booty, but the obstetrician must be able to help him be born in any position.
The third period is called the next and starts from the moment of the birth of the child, and ends with the appearance of the afterbirth. Normally, it lasts half an hour, and after fifteen minutes the placenta is separated from the uterine wall and is expelled from the womb with the last effort.
Postpartum separation delay
The reasons for the delay of the placenta in the uterine cavity may be its hypotension, placental accretion, anomalies in the structure or location of the placenta, placental adhesion to the uterine wall. Risk factors in this case are inflammatory diseases of the uterine mucosa, the presence of cesarean section scars, fibroids, and a history of miscarriages.
A symptom of placenta retention is bleeding in the third stage of labor and after it. Sometimes blood does not immediately flow out, but accumulates in the uterine cavity. Such latent bleeding can lead to hemorrhagic shock.
Placenta increment
The increment of the placenta is its tight attachment to the uterine wall. The placenta can lie on the mucosa, be immersed in the wall of the uterus to the muscle layer and grow through all layers, affecting even 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 attached 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 a child’s place is attached to the wall of the uterus, and discuss this point with the future mother in advance. If the doctor finds out about a similar anomaly in the location of the placenta during childbirth, then he must decide on the removal of the uterus.
Methods for manual separation of the placenta
There are several ways to manually remove the placenta. This can be manipulations on the surface of the abdomen of the woman in labor, when the latter is squeezed out of the uterine cavity, and in some cases, doctors are literally forced to get the placenta with the shells with their hands.
The most common is the Abuladze technique, when a woman obstetrician gently massages the front abdominal wall with her fingers, and then suggests she 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 to this, the bladder is catheterized by the puerperal, this stimulates the contraction of the muscles of the uterus. Oxytocin is administered intravenously to stimulate labor.
If manual separation of the placenta through the anterior abdominal wall is ineffective, then the obstetrician resorts to the internal compartment.
Postpartum separation technique
The technique of manual separation of the placenta is to remove it from the uterine cavity in pieces. An obstetrician in a sterile glove inserts his hand into the uterus. The fingers are maximally brought to each other and extended. She reaches the placenta by touch and carefully, with light chopping movements, separates it from the bosom wall. Manual removal of the placenta should be very careful so as not to cut through the uterine wall and cause massive bleeding. The doctor gives a sign to the assistant to pull on the umbilical cord and pull out the child seat and check its integrity. The midwife, meanwhile, continues to feel the walls of the uterus to remove all excess tissue and make sure that there are no pieces of the placenta inside, as this can provoke a postpartum infection.
Manual separation of the placenta involves uterine massage, when one doctor’s hand is inside and the other gently presses on the outside. Thus, uterine receptors are stimulated, and it contracts. The procedure is performed under general or local anesthesia under aseptic conditions.
Complication and consequences
Complications include postpartum haemorrhage and hemorrhagic shock associated with massive blood loss from the placenta vessels. In addition, manual separation of the placenta can be dangerous with perforation of the uterus and the development of postpartum endometritis or sepsis. In the most adverse circumstances, a woman risks not only her health and the opportunity to have children in the future, but also her life.
Prevention
In order to avoid problems in childbirth, you must properly prepare your body for pregnancy. First of all, the appearance of the child should be planned, because abortion violates to some extent the structure of the endometrium, which leads to tight attachment of the child's place in subsequent pregnancies. It is necessary to timely diagnose and completely treat the diseases of the genitourinary system, since they can affect reproductive function.
It is recommended to exclude accidental sexual relations without the use of barrier methods of contraception, observe personal hygiene and maintain the immune system in the autumn-spring period.
An important role is played by the timely registration of pregnancy. The sooner the better for the baby. Doctors obstetrician-gynecologists insist on a regular visit to the antenatal clinic during the period of gestation. Be sure to follow the recommendations, walks, proper nutrition, healthy sleep and exercise, as well as giving up bad habits.