Quantificação dos volumes do líquido amniótico e do embrião obtidos pela ultra-sonografia bidimensional e tridimensional no primeio trimestre da gestação

Abstract

SPARA, P. Quantitation of amniotic fluid and embryo volumes by twodimensional and three-dimensional ultrasonography in the first trimester of pregnancy. 2005. 133p. Tese de Doutorado -Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Ribeirão Preto, 2005.The objective of this study was to determine amniotic fluid and embryo volumes by two-dimensional and three-dimensional ultrasonography in normal pregnant women from the 8th to the 11th week of gestation. We made a prospective longitudinal study on 25 normal fetuses. Inclusion criteria were singleton fetuses and normal clinical and laboratory evaluation, and exclusion criteria were pregnant women with maternal diseases and/or diseases typical of pregnancy, smokers, and alcohol or drug users.All patients signed an informed consent form. The tests were performed by two observers using an ultrasonography apparatus model SA-9900 (MEDISON), a volumetric endovaginal transducer, a 5-6.5 Hz broad band and 120 o of visual field.Each pregnant woman was evaluated in the 8 th , 9 th , 10 th and 11 th week of gestation.The two-dimensional study consisted of the determination of volumetric measurements by a mathematical calculation based on the ellipsoid shape, with determination of total amniotic sac volume and embryo volume. In the threedimensional study the amniotic fluid volume was determined by the VOCAL technique. In both methods, the amniotic fluid volume was obtained by subtracting the volumetric measurement of the embryo from the measurement of the amniotic sac volume. Data were analyzed statistically by analysis of variance (ANOVA), by correlation and by regression analysis, with the level of significance set at p< 0.05 in all analyses. The amniotic fluid volume (V AF ) determined by two-dimensional ultrasonography increased from 5.45 to 39.52 cm 3 from the 8 th to the 11 th week (ANOVA -p< 0.05). There was a strong positive correlation between gestational age and V AF (p< 0.001, r 2 = 88.3%). In the three-dimensional study, V AF increased from 5.75 to 42.96 cm 3 from the 8 th to the 11 th week (ANOVA -p< 0.05). The correlation between gestational age and V AF was strong and positive (p< 0.001, r 2 = 98.1%). In conclusion, the volume of the amniotic fluid and of the embryo increased progressively from the 8th to the 11th week of gestation both when evaluated by two-dimensional and three-dimensional ultrasonography. The estimate of V AF obtained by three-dimensional ultrasonography was lower than that obtained by twodimensional ultrasonography in the 9th and 10th week of gestation and higher in the 11th week of gestation. The embryo volume obtained by the three-dimensional technique was larger than that obtained by the two-dimensional technique in all gestational weeks evaluated.