1, what is placenta?
After the fertilized egg is implanted into the maternal uterine cavity, the placenta begins to form gradually. Just as the roots of plants are stuck in the soil, the villi of fertilized eggs invade the endometrium and gradually extend, and the villi closely combine with the endometrium and gradually merge to form the placenta. Placenta is completely formed around 12 weeks of pregnancy.
The main function of placenta is to deliver nutrients and oxygen to the baby in the abdomen, and to discharge the fetal metabolites, such as urea nitrogen and carbon dioxide, to prevent the invasion of harmful substances from the mother and affect the health of the fetus. In addition, it can also produce hormones and various enzymes. Therefore, during the whole pregnancy, the placenta plays the role of nourishing the fetus, protecting the fetus, excreting metabolic waste and maintaining normal endocrine. Once the parturient gives birth, the placenta completes its mission and is excreted with the contraction of the uterus.
Placental insufficiency endangers the baby.
Placental insufficiency refers to the disorder of blood exchange between uterus and placenta before or after delivery, which leads to the impairment of placental function, low and declining placental function, fetal hypoxia, malnutrition, developmental retardation and fetal distress. The long-term consequence is that the number of fetal brain cells is reduced, and fetal growth is delayed, which may eventually make children lag behind normal children in their future intellectual development.
Clinically, placental insufficiency is divided into chronic, subacute and acute. The onset of chronic placental insufficiency is slow, easy to occur in the second and third trimester of pregnancy and can last for several weeks. Acute placental insufficiency is urgent, and the time is within ten minutes to several days. Subacute placental insufficiency is between acute and chronic.
2. Causes of placental insufficiency
1. About two weeks after the expected date of delivery of overdue pregnancy, the placenta begins to age and degenerate, and the blood flow decreases and its function declines. Prolonged delivery time is the most common factor leading to placental aging. At this time, the placental material exchange capacity can not meet the needs of the increased fetus, which will lead to fetal distress and endanger the fetus.
2. Maternal disease history When pregnant women suffer from hypertension, chronic nephritis, diabetes or pregnancy complicated with pregnancy-induced hypertension syndrome, systemic arteriole spasm or sclerosis will occur, resulting in insufficient blood supply to the placenta and damage to placental function. When pregnant women suffer from heart and lung diseases, severe protein deficiency, anemia, fever and other diseases, use certain drugs (diethylstilbestrol, anticancer drugs), and smoke too much, the oxygen content in maternal blood is reduced, and the nutrients supplied to the placenta are also reduced, resulting in placental insufficiency.
3, uterine factors such as pregnant women lying on their backs for a long time, suffering from uterine fibroids, uterine malformations and so on. , affecting the blood supply to the uterus, reducing the blood flow in the villous space, resulting in insufficient blood supply to the placenta.
4. Placental factors include small placenta, early placental abruption, placenta previa, vascular infarction (fibrous deposition), vasculitis, umbilical cord complications, etc. Can cause placental dysfunction.
5. Fetal factors Multiple pregnancy, fetal heart disease and fetal malformation.
3. How to check the placental function?
From the 36th week of pregnancy, we should go to the hospital regularly to check the function of the placenta and pay attention to the health of the placenta. The doctor will judge whether there is placental insufficiency or make further intervention according to your comprehensive situation. The following are common tests of placental function:
Fetal movement count
The easiest way is to count fetal movements, and pregnant women can monitor them themselves. Because fetal movement is closely related to placental blood supply, if placental function declines, the fetus can reduce its activity due to chronic hypoxia. Because of the different activity of each fetus, the number of times pregnant women induce fetal movement varies greatly, and the cumulative number of times in 12 hour ranges from ten to a hundred times, so every pregnant woman has her own fetal movement law. If the number of activities of the fetus in 12 hours is less than 10 times, or it drops by more than 50% every day and cannot be recovered, or it suddenly drops by more than 50%, it means that the fetus is hypoxic. Pregnant women should attach great importance to it, take the left lateral position in time, increase placental blood flow and go to the hospital for further examination and treatment.
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Placenta secretes chorionic gonadotropin, progesterone and placental prolactin. By examining these hormones secreted by placenta, we can see whether its placental function is normal.
Fetal heart rate monitoring
At present, non-stress test (NST) is widely used. If the fetal heart rate is accelerated during fetal movement, it is a normal reaction, indicating that the placental function is not bad, and there will be no stillbirth caused by fetal and placental dysfunction within one week.
B ultrasound examination
Including fetal biparietal diameter, placental function classification, amniotic fluid volume and so on.
4. Prevent placental insufficiency.
During pregnancy, you should take enough vitamins, calcium, iron, protein and other nutrients, and pay attention to a reasonable and balanced diet.
During pregnancy, especially in the third trimester, it is necessary to combine work and rest, adhere to moderate walking, and promote blood circulation throughout the body. You can count fetal movements at home and pay close attention to the health status of the baby in your stomach.
According to the doctor's request, do prenatal examination regularly. Especially pregnant women with pregnancy-induced hypertension syndrome and heart and kidney diseases, only in this way can placental dysfunction be found and treated in time.