Velamentous Cord Insertion

What is velamentous cord insertion (VCI)

The fetal blood vessels usually travel via the placenta and then reach the baby through the umbilical cord. So, the umbilical cord directly inserts into the placenta, protecting all parts of the blood vessels. However, in some cases, the cord inserts into the fetal membranes, making the blood vessels travel through the amnion and chorion (without the protection of the Wharton’s jelly) to reach the placenta.^{[1, 2]} It poses a significant risk of the exposed umbilical vessels getting damaged.^[3]

What causes velamentous insertion of the umbilical cord

There is no way to pinpoint the exact cause as there are a number of risk factors, including:

In vitro fertilization^[4]
Multiple pregnancy^[5]
An advanced maternal age
Having a history of an abnormal umbilical cord insertion in a previous pregnancy
Placenta previa^[3]
C-section in a previous pregnancy^[6]
Preeclampsia
Gestational diabetes^[7]

It may also be associated with placental trophotropism,^[8] a process in which the placenta tends to move to areas with better blood flow,^[9] so it can provide the fetus properly with oxygen and nutrients. An abnormal cord insertion is believed to have an association with higher levels of maternal serum hCG and lower maternal serum AFP^[10].

How is velamentous cord insertion detected

It is often detected during a transvaginal ultrasound with color imaging being a useful diagnostic method to confirm the anomaly.^[11]

What are the risks of velamentous cord insertion

A VCI does not cause any serious problem as long as the baby is in the uterus,^[12] as the abnormal insertion does not affect the oxygen and nutrient flow; however, it carries a significant risk of cord rupture and bleeding during labor and delivery.

With a mortality rate of bout 60%, vasa previa is a serious associated complication^[8] where the exposed umbilical vessels pass over the internal cervical opening, coming in the way of the baby if a natural birth is attempted.^[13] An abnormal insertion may sometimes turn into vasa previa, with statistics showing the two conditions to coexist in about 6% of singleton pregnancies with a VCI.^[14] In extreme cases, the baby may even die within a few minutes due to excessive bleeding.^[5]

There are a few more associated risks and complications that may have long term effects on the physical and mental growth of your baby. These include:

Intrauterine growth restriction (IUGR)^[10]
Abnormal fetal heartbeat during labor
Premature birth
Low birth weight
Down’s syndrome (trisomy 21)^[15]
Hypoxic ischemic encephalopathy (HIE)^[10]
Cerebral palsy (especially in monochorionic twins)^[16]
Stillbirth

Velamentous cord insertion management

Since there is no way to correct the abnormal insertion, close monitoring is the only way to make sure the baby stays healthy and grows properly. Regular ultrasonography usually helps with the purpose.^[10] An immediate cesarean section is necessary to save the baby if there is a rupture of the umbilical vessels or any sign of fetal distress.^[17] In case of vasa previa, an urgent c-section is done before the start of cervical dilation and labor.^{[18, 19]}

Apart from the medical management, you may be asked to avoid certain activities like running, climbing stairs, exercising and picking up heavy objects in the later stages. Bed rest may be prescribed in extremely high-risk cases.

How common is velamentous cord insertion

Velamentous insertion of the umbilical cord occurs in 1% of all singleton pregnancies, while its prevalence is as high as 15% in monochorionic twin pregnancies (identical twins sharing the same placenta).^[3] In vitro fertilization is one of the major risk factors and has been reported in around 14% of IVF pregnancies.^[4]It is more common in the later first and early second trimesters, with around 33% of the cases occurring between weeks nine and 12, while 26% cases are diagnosed between weeks 13 and 16.^[20]

Velamentous cord insertion ICD-9 and ICD-10 codes

The ICD-9-CM code used for VCI is 762.6,^[21] while its ICD-10 code is O43.1.^[22]

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