First-Trimester Ultrasound Volumetry

Measurement Techniques and Potential Application in the Prediction of Pregnancy Complications

Kwok Yin Leung; Teresa Ma; Betty YT Lau; Min Chen


Expert Rev of Obstet Gynecol. 2012;7(4):379-386. 

In This Article

Yolk Sac Volume

YSV was measured using the VOCAL method with 30° rotation[6] or XI VOCAL.[59] There was a poor correlation between YSV and GA or CRL.[6] The mean YSV increased from 0.063 cm3 at 7 weeks to 0.164 cm3 at 10 weeks.[6] Similar to another study,[60] the mean YSV increased in a linear fashion up to 10 weeks, then maintained a plateau until 11 weeks, and decreased thereafter.[6] This can probably be explained by the yolk sac degeneration process secondary to vascular depletion.[61] The absence or malformation of a yolk sac outside the normal growth pattern is associated with poor pregnancy outcomes.[62]


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