Value of ultrasound in the assessment of placenta - fetal umbilical cord

The article is professionally consulted by Master, Doctor Ly Thi Thanh Nha - Department of Obstetrics and Gynecology - Vinmec International General Hospital Da Nang. Doctor Nha has strengths and experience in fetal malformation ultrasound, 3D, 4D fetal ultrasound.

The placenta and umbilical cord are one of the important appendages when fetal ultrasound needs to be evaluated to detect fetal abnormalities. When detecting signs of disease risk, it can help control risk factors in labor and limit complications for mother and fetus.

The placenta is the connecting part between the mother and the fetus, usually round and attached to the muscle of the uterus. The placenta ensures the task of providing oxygen and nutrients necessary for the development of the baby. The placenta also helps protect the fetus from the risk of many factors from inside the mother's body and from the environment.
The umbilical cord is a narrow tube-like structure that connects the developing fetus to the placenta, bringing blood back and forth between the fetus and the placenta to provide nutrients, oxygen, and remove waste products. of the fetus. The umbilical cord consists of a vein that carries oxygen and nutrients from the placenta to the fetus and two arteries that transport waste from the fetus to the placenta (where waste is transferred into the mother's bloodstream and processed by the mother's kidneys).
Thus, the function of the placenta and the umbilical cord is very important to the development of the fetus. If an abnormality of these two components will cause significant effects on the fetus.

When the placental ultrasound helps to assess the normal or abnormal condition of the placenta, thereby helping to predict and give appropriate advice to pregnant women.
2.1 Normal placenta The normal placenta is semicircular, adjacent to the uterine wall, and can be clearly identified on ultrasound from around 11 weeks. Place of adhesions can be fundal attachment, anterior attachment. , back, right or left side. Ultrasound shows that the structure of the placenta and the uterine wall are separate from each other. The thickness of the placenta increases with gestational age.

2.2 Placental anomalies Placenta praevia: Placenta previa is a condition when the lower edge of the placenta attaches to, or covers the entire internal opening of the cervix. The division of placenta previa by the position of each other includes the central placenta previa (when the placenta completely covers the cervical os) and the semicentral placenta previa (when the placenta does not completely cover the endocervical foramen). bow). Determine the position of attachment of the inferior edge of the placenta after 28 weeks. This condition requires close monitoring because of the risk of bleeding during labor. Placement of comb teeth: Placenta of comb teeth is a condition where the position of the placenta is abnormal. In which placental hairs can penetrate the mucosa into the muscular layer of the uterus. About 5-10% of cases where placenta previa occurs together with comb teeth. The placenta is very difficult to clean after giving birth, causing retained placenta, the cause of postpartum bleeding and increasing the risk of infection. A hysterectomy is usually required to rule out the risk of bleeding, but it can also invade nearby organs. Ovulation: When all or part of the placental spines degenerate into follicles, no fetal images are seen. The ultrasound image of the placenta showed an enlarged placenta and many scattered water sacs. The present pregnancy is usually underdeveloped and sometimes malformed in the case of partial ovum. Placental hemangioma: Very rarely, vascular tumor due to abnormal proliferation forms a mass in the chorion of the placenta. This tumor usually does not affect the development of the fetus, but if it is large, it can cause complications in both mother and baby. Placental ultrasound can help monitor and predict abnormalities. Subchorionic hematoma in the placenta : Ultrasound of the placenta shows a subchoroidal hematoma that contains blood and is usually located next to the umbilical cord, which is the result of rupture of a blood vessel leaving the chorion. This condition can cause premature birth. Placental abruption : After a direct or indirect trauma, women experience abdominal pain, vaginal bleeding or not, uterine wall tension, signs of preterm labor and shock, affecting the life of the baby. women and fetuses. This could be a sign of placental abruption, which can be detected on ultrasound.

3.1 Normal umbilical cord Location located in the center of the placenta, sometimes next to the center or edge of the placenta. The structure of the umbilical cord consists of 3 blood vessels, 2 arteries, and 1 vein that form the helix. The umbilical cord forms 5 weeks after conception and gradually grows longer, reaching its maximum length by the 28th week of pregnancy, the average length of the umbilical cord is about 50-60cm.

3.2 Abnormalities of the umbilical cord Single-arterial umbilical cord: Occurs about 1% in singleton pregnancies and about 5% in multiples. The umbilical cord contains only two blood vessels, instead of the usual three. Fetuses with an umbilical artery have a higher risk of birth defects such as heart, nervous system, urinary system and chromosomal abnormalities. Therefore, when an umbilical artery is diagnosed, pregnant women should do some intensive prenatal testing to diagnose or rule out associated congenital anomalies. Long umbilical cord: When the length of the umbilical cord is more than 80cm, it is diagnosed as a long umbilical cord. This condition leads to the umbilical cord wrapped around the body and neck of the fetus, if wrapped tightly can cause fetal anemia. Short umbilical cord: The length of the umbilical cord is less than 35cm. Sometimes only 10cm long, the umbilical cord is very short. Usually associated with other serious abnormalities of the body. Thin umbilical cord: The umbilical cord ultrasound measures a decrease in the diameter of the umbilical cord, from 5 to 6 mm, which is common in the case of hypothermia. Umbilical cord attachment: This is a condition in which the umbilical cord does not attach to the center of the placenta but to the edge of the placenta. May be the cause of intrauterine growth retardation. Umbilical cord clinging to membranes: That is, the umbilical cord blood vessels do not attach to the placenta as usual, but only attach to the amniotic membrane and then to the placenta. Blood vessels circulating in the membrane freely, unprotected by the colloid, can be compressed or ruptured during labor, increasing the mortality rate at birth. Umbilical cord cysts: Functional cysts are visible in the first 3 months of pregnancy, and usually disappear in the second trimester. In the case of organic cysts that persist after 14 weeks, they usually do not go away during pregnancy. At present, the prognostic significance of the location and size of the cystic tumor remains unclear.

Ultrasound assessment of the umbilical cord and placenta is very important in prenatal diagnosis, helping to assess the risk and prognosis for the fetus. Therefore, when pregnant, it is necessary to regularly check periodically to detect abnormalities of the fetus as well as its appendages.
Vinmec International General Hospital offers a Package Maternity Care Program for pregnant women right from the first months of pregnancy with a full range of antenatal care visits, periodical 3D and 4D ultrasounds and routine tests to ensure that the mother is healthy and the fetus is developing comprehensively.