Umbilical cord insertion anomalies
Normal umbilical cord insertion can be accompanied by rare pathologies. With marginal insertion, the cord attaches to the periphery of the placenta, while pregnancy and labor typically proceed without complications.
A more dangerous condition is velamentous cord insertion, where the cord attaches to the fetal membranes at a distance from the margin, and vessels run to the placenta through the membranes. This pathology increases the risk of preterm birth and fetal growth restriction. If the vessel-containing segment is located over the internal cervical os, it is referred to as vasa praevia (fetal vessel presentation). During labor, this poses a threat of vessel rupture, acute hypoxia, and fetal death.
Pathology of the number of umbilical vessels
Normally, the umbilical cord contains three vessels. However, a single umbilical artery occurs, which is diagnosed three to four times more frequently in maternal diabetes mellitus and multiple pregnancies.
- Malformations and chromosomes: In 25–50% of cases, the pathology is combined with fetal developmental malformations, and the frequency of chromosomal abnormalities reaches 14%.
- Diagnostics: On a cross-section of the umbilical cord loop, ultrasound visualizes only two vessels. Color Doppler mapping significantly increases diagnostic accuracy.
Placental hyperplasia and hypoplasia
Changes in placental weight indicate serious intrauterine development disorders:
- Placental hyperplasia: organ weight is 1000 g or more. Observed in hemolytic disease of the fetus, diabetes mellitus, multiple pregnancy, and intrauterine infections. Detected using ultrasound.
- Placental hypoplasia: a decrease in organ weight to less than 400 g at term pregnancy. It serves as an indirect sign of placental insufficiency and accompanies preeclampsia, hypertension, and fetal growth restriction.
Placental infarctions and neoplastic processes
Hemodynamic disorders and neoplasms significantly affect pregnancy outcomes:
- Placental infarctions: develop due to microthrombosis and spasm of spiral arteries in women with hypertension and preeclampsia. Small marginal infarctions are a variant of normal, while large and multiple ones lead to hypoxia and fetal growth restriction.
- Placental chorioangioma: a benign tumor originating from fetal capillaries. In large sizes, it can cause premature placental abruption.
- Trophoblastic disease: includes hydatidiform mole, invasive mole, choriocarcinoma, and placental site trophoblastic tumors. Malignant forms are characterized by rapid metastasis, but are successfully treated with chemotherapy.
The umbilical cord needs a triple alliance: two arteries and a vein. If there is only one artery, look for fetal malformations.
Class and exam questions
Why is velamentous cord insertion dangerous?
It can be combined with chromosomal abnormalities and fetal growth restriction. The main threat arises in vasa praevia (vasa praevia), when vessel rupture during labor and fetal death from hemorrhage are possible.
What does a placental mass greater than 1000 grams indicate?
Such placental hyperplasia is characteristic of maternal diabetes mellitus, multiple pregnancy, intrauterine infection, and hemolytic disease of the fetus due to Rh sensitization.
In which cases are placental infarctions considered pathological?
Small marginal infarctions correspond to physiological aging of the placenta and are safe. Large or multiple infarctions cause hypoxia and fetal growth restriction.
What else to study on this topic
- Microscopic picture of hydatidiform mole and chorionic villi
- Differential diagnosis of malignant trophoblastic tumors
- Management features for patients with placental chorioangioma
- Delivery tactics in single umbilical artery
- Criteria for assessing severity in placental infarctions
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