Velamentous cord insertion
Updates to Article Attributes
Velamentous cord insertion is one of the types of abnormal umbilical cord insertion into the placenta.
Epidemiology
The estimated incidence is ~1% in singleton and 9-15% in twin pregnancies, respectively 11. It is also more common in placenta previa than in normally located placentas. The prevalence may be slightly higher in stillbirths, particularly from multifetal pregnancies.
Pathology
In a velamentous cord insertion, the umbilical cord inserts into the fetal (chorio-amniotic) membranes outside the placental margin and then travels within the membranes to the placenta (between the amnion and the chorion). It is thought to result from remodelingremodelling of the placenta as a response to factors that affect the distribution of uterine blood flow (a process known as trophotropism 5). A marginal cord insertion may evolve into a velamentous cord insertion as the pregnancy progresses 6. Some also support an abnormal primary implantation due to the obliquity of the embryo during implantation as a cause.
Associations
- bilobed placenta
- increased incidence in twin pregnancy
- uterine anomalies 10
- presence of an intrauterine contraceptive device (IUCD) 10
- single umbilical artery 6
- placenta previa
Radiographic features
Antenatal ultrasound
Ultrasound allows direct visualisation of the cord implantation to a site outside the placenta.
A velamentous cord insertion may be detected as early as the first-trimester scan 4. Antenatal ultrasound is considered to have a variable sensitivity (69-100%) but high specificity (99-100%) for revealing abnormal placental cord insertion sites, including velamentous insertions 5,8.
Color Doppler greatly aids in identification.
Complications
- type I vasa previa
- increased risk of intrauterine growth restriction (IUGR)
- increased risk of growth discordance if in a twin pregnancy
- increased risk of twin to twin transfusion syndrome
Treatment and prognosis
Treatment somewhat depends on the location of velamentous vessels and if in the lower segment, a caesarean section to avoid the risks of a vasa previa is often considered.
See also
- Battledore placenta (marginal cord insertion)
-<p><strong>Velamentous cord insertion</strong> is one of the types of <a href="/articles/abnormal-cord-insertion">abnormal umbilical cord insertion</a> into the <a href="/articles/placenta">placenta</a>.</p><h4>Epidemiology</h4><p>The estimated incidence is ~1% in singleton and 9-15% in twin pregnancies, respectively <sup>11</sup>. It is also more common in placenta previa than in normally located placentas. The prevalence may be slightly higher in stillbirths, particularly from multifetal pregnancies.</p><h4>Pathology</h4><p>In a velamentous cord insertion, the umbilical cord inserts into the fetal (chorio-amniotic) membranes outside the placental margin and then travels within the membranes to the placenta (between the amnion and the chorion). It is thought to result from remodeling of the placenta as a response to factors that affect distribution of uterine blood flow (a process known as trophotropism <sup>5</sup>). A <a href="/articles/marginal-cord-insertion">marginal cord insertion </a>may evolve into a velamentous cord insertion as the pregnancy progresses <sup>6</sup>. Some also support an abnormal primary implantation due to obliquity of the embryo during implantation as a cause.</p><h5>Associations</h5><ul>- +<p><strong>Velamentous cord insertion</strong> is one of the types of <a href="/articles/abnormal-cord-insertion">abnormal umbilical cord insertion</a> into the <a href="/articles/placenta">placenta</a>.</p><h4>Epidemiology</h4><p>The estimated incidence is ~1% in singleton and 9-15% in twin pregnancies, respectively <sup>11</sup>. It is also more common in placenta previa than in normally located placentas. The prevalence may be slightly higher in stillbirths, particularly from multifetal pregnancies.</p><h4>Pathology</h4><p>In a velamentous cord insertion, the umbilical cord inserts into the fetal (chorio-amniotic) membranes outside the placental margin and then travels within the membranes to the placenta (between the amnion and the chorion). It is thought to result from remodelling of the placenta as a response to factors that affect the distribution of uterine blood flow (a process known as trophotropism <sup>5</sup>). A <a href="/articles/marginal-cord-insertion">marginal cord insertion </a>may evolve into a velamentous cord insertion as the pregnancy progresses <sup>6</sup>. Some also support an abnormal primary implantation due to the obliquity of the embryo during implantation as a cause.</p><h5>Associations</h5><ul>
-<li>presence of an <a href="/articles/intra-uterine-contraceptive-device-1">intrauterine contraceptive device (IUCD)</a> <sup>10</sup>- +<li>presence of an <a href="/articles/intrauterine-contraceptive-device-1">intrauterine contraceptive device (IUCD)</a> <sup>10</sup>
-</ul><h4>Radiographic features</h4><h5>Antenatal ultrasound</h5><p>Ultrasound allows direct visualisation of the cord implantation to a site outside the placenta.</p><p>A velamentous cord insertion may be detected as early as the first-trimester scan <sup>4</sup>. Antenatal ultrasound is considered to have variable sensitivity (69-100%) but high specificity (99-100%) for revealing abnormal placental cord insertion sites, including velamentous insertions <sup>5,8</sup>.</p><p>Color Doppler greatly aids in identification.</p><h4>Complications</h4><ul>- +</ul><h4>Radiographic features</h4><h5>Antenatal ultrasound</h5><p>Ultrasound allows direct visualisation of the cord implantation to a site outside the placenta.</p><p>A velamentous cord insertion may be detected as early as the first-trimester scan <sup>4</sup>. Antenatal ultrasound is considered to have a variable sensitivity (69-100%) but high specificity (99-100%) for revealing abnormal placental cord insertion sites, including velamentous insertions <sup>5,8</sup>.</p><p>Color Doppler greatly aids in identification.</p><h4>Complications</h4><ul>