The cord and the placenta are always being assessed for anomalies after birth. There are instances wherein the placenta in a woman is unusual in size, owing to some conditions that the woman is experiencing. The cord also has its own normal appearance that when something deviates from it, it may denote an anomaly.
Anomalies of the Cord
Two Vessel Cord
- A normal cord has one vein and two arteries.
- If one of the umbilical arteries is absent, this may denote that the infant may have congenital heart and kidney anomalies.
- This is because the insult that caused the loss of the vessel may have affected other mesoderm germ layer structures as well.
- Immediate inspection of the cord as to how many vessels are present must be performed after birth before the cord starts to dry.
- Drying distorts appearance of the vessels, making it difficult to discern the number of vessels present.
- The number of vessels must be documented appropriately after inspection.
- If the infant has only two vessels, he needs to be observed carefully for other anomalies during the newborn period.
Unusual Cord Length
- The length of the umbilical cord varies in every infant, but in some, abnormal lengths may occur.
- An unusually short umbilical cord may predispose the fetus to premature separation of placenta or an abnormal fetal lie.
- An unusually long cord has a great tendency of twisting or knotting.
- A cord naturally forms a knot but the natural pulsations of the blood through the vessels and the muscular vessel walls usually keep the blood flow adequate.
- A cord wrapped once around the fetal neck is not unusual but should not interfere to fetal circulation.
Anomalies of the Placenta
- The normal placenta weighs approximately 500 g and is 15 to 20 cm in diameter and 1.5 to 3.0 cm thick.
- Placenta succenturiata is a placenta that has one or more accessory lobes connected to the main placenta by the blood vessels.
- This is not a fetal abnormality; however, it must be recognized upon assessment after birth.
- The small lobes may be retained in the uterus after birth leading to severe maternal hemorrhage.
- If you look closer at the placenta, it may appear torn at the edge or torn blood vessels extend beyond the edge of the placenta.
- Remaining lobes are removed from the uterus manually to prevent maternal hemorrhage as a result of poor uterine contraction.
- Normally, the chorion membrane begins at the edge of the placenta and spreads to cover the fetus.
- The fetal side of the placenta is not usually covered by the chorion.
- In placenta circumvallata, the fetal side of the placenta is covered with chorion.
- The umbilical cord enters the placenta at the usual midpoint, and large vessels spread out from there.
- They end abruptly at the point where the chorion folds back into the surface.
- In placenta marginata, the fold of the chorion reaches just to the edge of the placenta.
- Placenta accrete refers to an unusually deep attachment of the placenta to the uterine myometrium that the placenta will not loosen and deliver.
- Never attempt to remove it because it might lead to extreme hemorrhage because of its deep attachment.
- Hysterectomy or treatment with methotrexate to destroy the still-attached tissue is the recommended treatment of choice.
- Battledore placenta refers to the cord that is inserted marginally rather than centrally.
- This is a rare anomaly and it has no known clinical significance.
Velamentous Insertion of the Cord
- Velamentous insertion of the cord occurs when the cord, instead of entering the placenta directly, separates into small vessels that reach the placenta by spreading across a fold of amnion.
- This is most commonly found with multiple gestations.
- It can be associated with fetal anomalies, so an infant born with this type of placenta must be examined carefully.
- The umbilical vessels of a velamentous cord insertion cross the cervical os and therefore deliver before the fetus.
- The vessels may tear with cervical dilatation, just as the placenta previa may tear.
- Ensure that you can identify the structures before inserting any instrument to prevent accidental tearing of a vasa previa which could end in sudden fetal blood loss.
- With either placenta previa or vasa previa, there is sudden , painless bleeding that occurs with the beginning of cervical dilatation.
- Vasa previa can be confirmed by ultrasound.
- If vasa previa is confirmed, the infant needs to be born via cesarean delivery.
Practice Quiz: Placental and Cord Anomalies
Here’s a 6-item practice quiz about the topic: Placental and Cord Anomalies.
1. The nurse observed that a newborn has only one umbilical artery. What condition is associated with this condition?
2. A short umbilical cord may lead to:
3. Small lobes were retained in the uterus after birth in placenta succenturiata, which could lead to:
4. Which of the following is not an anomaly of the placenta?
A. Vasa previa
B. Two Vessel cord
C. Placenta circumvallata
D. Placenta succenturiata
5. Velamentous insertion of the cord would happen most likely in a woman who has:
6. Which of the following is a sign of vasa previa?
A. A single umbilical artery.
B. Sudden painless bleeding.
C. A short umbilical cord.
D. The fetal side of the placenta is covered by chorion.
Answers and Rationale
1. Answer: B. Congenital Heart Disease
- B: If the newborn is observed to have one umbilical artery, congenital heart anomaly should be suspected.
- A: Battledore placenta is an anomaly of the placenta that refers to the cord that is inserted marginally rather than centrally.
- C: Rheumatic heart disease is not associated with a single umbilical artery.
- D: Liver disease is not associated with only one umbilical artery.
2. Answer: C. Premature separation of placenta.
- C: A short umbilical cord may predispose to premature separation of placenta.
- A: Cephalopelvic disproportion is not a result of a short umbilical cord.
- B: Labor is seldom affected by the length of cord.
- C: Macrosomia occurs with women who have diabetes or developed gestational diabetes.
3. Answer: D. Severe hemorrhage
- D: The uterus would attempt to expel any foreign body left inside after birth, resulting in severe maternal hemorrhage.
- A: Severe dehydration is a secondary effect of hemorrhage.
- B: If left untreated, the woman might fall into coma because of severe bleeding.
- C: Hypotension occurs when there is a sudden drop of maternal blood pressure.
4. Answer: B. Two Vessel cord
- B: A two-vessel cord is an anomaly of the cord.
- A: Vasa previa is an anomaly of the placenta.
- C: Placenta circumvallata is an anomaly of the placenta.
- D: Placenta succenturiata is an anomaly of the placenta.
5. Answer: A. Multiple gestation
- A: Multiple gestation predisposes a woman to velamentous insertion of the cord.
- B: Hypertension does not cause velamentous insertion of the cord.
- C: Gestational diabetes predisposes the fetus to macrosomia or hypoglycemia upon birth.
- D: Placenta previa can cause maternal hemorrhage and not velamentous insertion of the cord.
6. Answer: B. Sudden painless bleeding.
- B: Sudden painless bleeding is associated with vasa previa.
- A: A single umbilical artery occurs in a two-vessel cord.
- C: A short umbilical cord happens in a woman with an unusual cord length.
- D: When the fetal side of the placenta is covered by chorion, it refers to placenta circumvallata.