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

Gestational Sac Fluid Volume

The gestational sac fluid volume (GSFV) is obtained by subtracting the EV from the GSV after measuring them using VOCAL, with a rotational step of 30° rotation.[33] The GSFV can also be measured using the multiplanar method or VR.[55] SonoAVC is automatic, but may significantly underestimate GSFV.[51]

There is a significant correlation between GSFV and GA or CRL.[33] Mean GSFV increased by approximately five- to six-fold from 3.97 cm3 at 7–7+6 weeks to 23.33 cm3 at 10–10+6 weeks of pregnancy.[33] However, the corresponding range of GSFV was wide at 1.17–10.97 cm3 (~tenfold) and 11.93–32.41 cm3 (~threefold), respectively.[33] Mean GSFV increased by approximately six- to seven-fold from 7.81 to 50.28 cm3 for a CRL increase from 12 to 40 mm.[33] The GSFV/EV ratio decreased with GA.[55] In normal pregnancies, there was a progressive increase in amniotic fluid from 8 to 11 weeks of gestation.[57] Abnormal amniotic fluid volumes may indicate a pathology associated with adverse outcomes,[58] and further studies are required.


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