Amniotic shelf
Updates to Article Attributes
Amniotic shelf (also known as an amniotic sheet 4) refers to a a sheet like projection that can result can result fromuterine synechiae that has been encompassed by the expanding chorion and amnion. In contrast to amniotic bands, they are not thought to be associated with any fetal deformity.
Epidemiology
The estimated prevalence is at around 0.45-0.47% of pregnancies 5.
Pathology
They are composed of four distinct layers: two layers of chorion sandwiched between two layers of amnion.
Radiographic features
Antenatal ultrasound
They may be are seen as 'shelves' inshelf like thick bands and communicating along its entire length with the amniotic cavityuterine wall, thus having a base and a free edge. Colour Doppler may demonstrate flow within the band.
Complications
TheyWhen large they can be result in abnormal fetal presentations (e.g breech presentation) by reducingdue to reduced fetal movement by compartmentalisingcompartmentalizing amniotic fluid 5.
Prognosis
Most amniotic amniotic sheets are considered benign (especially if they are incomplete 2). But there is some evidence that complete amniotic sheets may be associated with adverse fetal outcome2. Some authors suggest that perpendicular, in contrast to non-perpendicular, amniotic sheets are more commonly associated with a breech presentation at term 3.
Differential diagnosis
If adjacent to the placenta on ultrasound consider:
See also
-<p><strong>Amniotic shelf</strong> (also known as an <strong>amniotic sheet </strong><sup>4</sup>) refers to a sheet like projection that can result from <a href="/articles/asherman-syndrome">uterine synechiae</a> that has been encompassed by the expanding chorion and amnion. In contrast to <a href="/articles/amniotic-bands">amniotic bands</a>, they are not thought to be associated with any fetal deformity. </p><h4>Epidemiology</h4><p>The estimated prevalence is at around 0.45-0.47% of pregnancies <sup>5</sup>.</p><h4>Pathology</h4><p>They are composed of four distinct layers: two layers of chorion sandwiched between two layers of amnion.</p><h4>Radiographic features</h4><h5>Antenatal ultrasound</h5><p>They may be are seen as 'shelves' in the amniotic cavity.</p><h4>Complications</h4><p>They can be result in <a href="/articles/abnormal-fetal-presentation">abnormal fetal presentations </a>(e.g breech presentation) by reducing fetal movement by compartmentalising amniotic fluid <sup>5</sup>.</p><h4>Prognosis</h4><p>Most amniotic sheets are considered benign (especially if they are incomplete <sup>2</sup>). But there is some evidence that complete amniotic sheets may be associated with adverse fetal outcome<sup>2</sup>. Some authors suggest that perpendicular, in contrast to non-perpendicular, amniotic sheets are more commonly associated with a breech presentation at term <sup>3</sup>.</p><h4>Differential diagnosis</h4><p>If adjacent to the placenta on ultrasound consider:</p><ul><li><a href="/articles/circumvallate-placenta">circumvallate placenta</a></li></ul>- +<p><strong>Amniotic shelf</strong> (also known as an <strong>amniotic sheet </strong><sup>4</sup>) refers to a sheet like projection that can result from <a href="/articles/asherman-syndrome">uterine synechiae</a> that has been encompassed by the expanding chorion and amnion. In contrast to <a href="/articles/amniotic-bands">amniotic bands</a>, they are not thought to be associated with any fetal deformity. </p><h4>Epidemiology</h4><p>The estimated prevalence is at around 0.45-0.47% of pregnancies <sup>5</sup>.</p><h4>Pathology</h4><p>They are composed of four distinct layers: two layers of chorion sandwiched between two layers of amnion.</p><h4>Radiographic features</h4><h5>Antenatal ultrasound</h5><p>They may be are seen as shelf like thick bands and communicating along its entire length with the uterine wall, thus having a<span style="line-height:1.6"> base and a free edge. Colour Doppler may demonstrate flow within the band. </span></p><h4>Complications</h4><p>When large they can result in <a href="/articles/abnormal-fetal-presentation">abnormal fetal presentations </a>(e.g breech presentation) due to reduced fetal movement by compartmentalizing amniotic fluid <sup>5</sup>.</p><h4>Prognosis</h4><p>Most amniotic sheets are considered benign (especially if they are incomplete <sup>2</sup>). But there is some evidence that complete amniotic sheets may be associated with adverse fetal outcome<sup>2</sup>. Some authors suggest that perpendicular, in contrast to non-perpendicular, amniotic sheets are more commonly associated with a breech presentation at term <sup>3</sup>.</p><h4>Differential diagnosis</h4><p>If adjacent to the placenta on ultrasound consider:</p><ul><li><a href="/articles/circumvallate-placenta">circumvallate placenta</a></li></ul><h4>See also</h4><ul><li><a href="/articles/intrauterine-membrane-in-pregnancy">intrauterine membrane in pregnancy</a></li></ul>
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