Title: OP05.01: 3D ultrasound volumetry-growth abnormalities of the gestational sac in the first trimester of pregnancy: relation to pregnancy outcome
Abstract: The aim of the study was to measure the volume of the gestational sac during the first trimester of pregnancy and find any relationship between growth abnormalities of the gestational sac and severe complications of pregnancy in the sense of loss of pregnancy or preterm delivery. The volume was measured using 3D ultrasound and VOCAL technique. We measured 335 chorionic cavities and 224 amniotic cavities in 335 singleton pregnancies between the 5th and 14th weeks of gestation. Adverse pregnancy outcome occurred in 34 cases. All measurements were done by two independent investigators. We found a relation between gestational age and gestational sac volume: ln(V_CD) = 24.443 + 6.5571 × lg(t) in pregnancies with normal outcome, ln(V_CD) = − 1.262 + 1.4082 × ln(t) in the cases of pregnancy loss. The regression analysis difference is statisticaly significant (F-test, P < 0.0001). The measurements of two independent investigators were in strong correlation (0.97). There is strong concordance in dating of gestation using Wisser and Hadlock until the 90th day of gestation; both manners of dating become divergent after the 90th day of gestation. Volume measurements of the gestational sac in the first trimester could be one of the first methods that could assess the development and prognosis of pregnancy. There is a difference in growth of the chorionic cavity in normal- and abnormal-ending pregnancies. In the previous part of this study we found a strong positive linear correlation between CRL and gestational sac volume in normal singleton pregnancies. It was suggested in previous studies that the growth of the gestational sac is abnormal in cases of miscarriage. At present this method seems to be unlikely to provide useful predictions of the major chromosomal defects.