Placenta: what it is, functions and main changes

The placenta is an organ formed during pregnancy, whose main role is to promote communication between the mother and the fetus and thus guarantee the ideal conditions for the development of the fetus. The main functions of the placenta are:

  • Provide nutrients and oxygen to the baby;
  • Stimulate the production of hormones essential for pregnancy;
  • Provide immunological protection to the baby;
  • Protect the baby against impacts on the mother’s belly;
  • Eliminate waste produced by the baby, such as urine.

The placenta is essential for the baby’s development, however, during pregnancy, it can undergo unwanted changes, bringing risks and complications for the mother to the baby.

How the placenta is formed

The formation of the placenta, as soon as implantation in the uterus occurs, is formed by cells from both the uterus and the baby. The growth of the placenta is fast and already in the third trimester of pregnancy, it is bigger than the baby. At about 16 weeks of gestation, the placenta and the baby are the same size, and by the end of the pregnancy the baby is already about 6 times heavier than the placenta.

The placenta is eliminated at delivery, whether cesarean or natural. During normal delivery, the placenta spontaneously leaves after 4 to 5 uterine contractions, which are much less painful than the uterine contractions that happen during the baby’s departure.

Most common placental changes

The ideal is for the placenta to remain intact throughout the pregnancy so that the baby’s development happens normally. However, there may be some changes in the placenta during pregnancy, which can have consequences for the mother and baby if the necessary measures are not taken. Some changes that can affect the placenta are:

1. Placenta previa

The placenta previa, also called the low placenta, happens when the placenta develops partially or totally in the lower region of the uterus, which can prevent normal delivery. The placenta previa is common in early pregnancy and is not very worrying, because with the growth of the uterus, throughout pregnancy, it is possible that the placenta is moved to the correct location, allowing for normal delivery.

However, when the placenta previa persists until the third trimester of pregnancy, it can interfere with the baby’s development and delivery. This change is more frequent in women who are pregnant with twins, who have uterine scars, who are over 35 years old or who have had a previous placenta.

The occurrence of low placenta can be perceived through vaginal bleeding, it is important to consult the gynecologist and / or obstetrician to make the diagnosis and to reduce the risk of premature birth and complications during delivery. See how the diagnosis of placenta previa is made and how is the treatment.

2. Placental detachment

The detachment of the placenta corresponds to a situation in which the placenta is separated from the wall of the uterus, with very strong vaginal bleeding and abdominal colic. Due to the separation of the placenta, there is a decrease in the amount of nutrients and oxygen sent to the baby, interfering with its development.

Placental detachment can occur more frequently after the 20th week of pregnancy and can result in premature delivery. Know what to do in case of placental detachment.

3. Placenta accreta

The placenta accreta is a situation in which the placenta has an abnormal fixation to the uterus, resisting to leave at the time of delivery. This problem can cause hemorrhages requiring blood transfusion and, in the most severe cases, complete removal of the uterus, in addition to putting the woman’s life at risk.

4. Calcified or aged placenta

It is a normal process and is related to the degree of development of the placenta. This change is only a problem if the placenta is classified as grade III before 34 weeks, as it can cause a slow growth rate of the fetus. In general, the woman has no symptoms and this problem is identified by the doctor on routine ultrasounds.

Learn more about the degrees of maturation of the placenta .

5. Placental infarction or placental thrombosis

Placental infarction occurs when there is a clogged blood vessel in the placenta, which characterizes a thrombosis and results in a decrease in the amount of blood that goes to the baby. Although this complication can cause miscarriages, it can also not cause problems with pregnancy and go unnoticed. Check out what to do in case of placental thrombosis .

6. Uterine rupture

It is the rupture of the uterine musculature during pregnancy or childbirth, which can cause premature birth and maternal or fetal death. Uterine rupture is a rare complication, treated with surgery during childbirth, and its symptoms are severe pain, vaginal bleeding and decreased fetal heartbeat.

To prevent and identify changes in the placenta before the onset of serious problems, one should follow routine consultations with the obstetrician and perform the necessary ultrasound tests at each stage of pregnancy. In cases of vaginal bleeding or severe uterine pain, a doctor should be consulted.

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