15 th World Congress on Ultrasound in Obstetrics and Gynecology Oral communication abstracts Comment: In CHD fetuses, increased DV Index, associated with reduced forward ductal flow to the right atrium, well correlates with increased right atrial pressure occurring in right outflow tract obstruction or in hypoplastic left ventricle. On the contrary in IUGR fetuses with increased DV Index and compensatory ductal dilatation, normal left cardiac output suggests normal myocardial function due to a maintained or even increased forward flow through the DV to right atrium. OC24.04 Relationship between prenatal Doppler findings and neurodevelopmental outcome at 2 years of age in intrauterine growth restriction (IUGR) A. Baschat , N Hashmi, M. L. Kush, R. Viscardi, C. R. Harman University of Maryland, Baltimore, USA Objective: We sought to determine if cardiovascular deterioration in IUGR fetuses is related to poor neurodevelopment. Material and methods: IUGR fetuses with an abdominal circum- ference < 5th%, elevated umbilical artery (UA) Doppler index and normal Karyotype were prospectively studied. Arterial and venous Doppler results, Apgar score, cord artery blood gas, birthweight (BW), gestational age (GA) and neonatal morbidity (NM) were related to neurodevelopment at 24 month corrected age as assessed by the Maryland Development screen (MDS). Global delay was diagnosed if an infant failed the MDS for 2 or more domains (gross and fine motor, language adaptive, social emotional and cognition). Cerebral palsy (CP) was based on typical motor findings. Results: 35 of 54 patients completed the study. There were 5 stillbirths, 9 neonatal deaths, 1 infant death and 4 lost to follow-up. 21 fetuses had absent/reversed UA diastolic velocity (AREDV) and 14 abnormal VD. Delivery was at a median GA of 30.2 weeks with a median BW of 910 grams. 10 infants had normal development, 10 (29%) had single domain delay, 24 (69%) global delay and 4 (11%) infants had CP. UA AREDV was associated with cognitive delay (RR 1.7). and CP (RR 1.5) and VD with abnormal tone (RR 3.3) and motor delay (RR 3.5). Major NM was related to abnormal tone (RR 2.7), motor delay (RR 1.9) and CP (RR 1.5, p < 0.05 for all). Logistic regression showed that gestational age was the main determinant of tone, motor, global delay and CP, while UA AREDV was the main determinant of cognitive delay. In addition UA and VD were independent contributors to CP and motor delay (all, p < 0.05). Conclusion: Fetal cardiovascular compromise is an independent predictor of poor neurodevelopment. Extreme placental blood flow resistance influences cognitive development while abnormal venous Doppler impacts motor, tone and global development. After delivery prematurity and associated morbidities become primary determinants. OC24.05 The proportion of umbilical blood shunting through the ductus venosus in nonhuman primate fetuses M. Tchirikov 1 , H. J. Schr ¨ oder 1 , N. Schlabritz-Loutsevitch 2 , N. Beindorff 1 , P. W. Nathanielsz 2 , K. Hecher 1 1 University Medical Center Hamburg-Eppendorf, Germany, 2 New York University School of Medicine, USA Objectives: The increased shunting of blood through the ductus venosus (DV) during stress situations is an important mechanism that ensures fetal survival. Although primate fetuses may serve to study the function of this important venous shunt the rate of DV shunting has not been determined in non-human primates under normal conditions. Methods: DV shunting was measured in 11 marmoset (8 mothers) and 8 singleton baboon fetuses in mid and late gestation using Doppler ultrasound. Results: Average DV shunting in marmosets was 41 ± 8% (Mean±SD), and 28 ± 8% in baboon fetuses. Umbilical vein (UV) blood volume rate increased significantly in baboons with gestational age (UV flow volume =−111.8 + 1.6 GA, r = 0.94, p < 0.05) and slightly in marmosets (UV flow volume =−10.37 + 0.13 GA, r = 0.42, p > 0.05). Both UV diameter (r = 0.84) and the time averaged mean UV flow velocity in baboons depended on GA (r = 0.8, p < 0.05). The extreme pulsation was found in marmoset fetuses in the UV (PI = 1.3 ± 0.9) and the DV (PI = 1.9 ± 1.2) with zero blood flow velocity during atrial contraction. Conclusions: A high level of pulsation was observed in the umbilical vein in marmoset fetuses. DV shunting in marmosets was higher than in baboon fetuses. OC24.06 Short term effect of betamethasone administration on MCA blood flow velocimetry on preterm intrauterine growth restricted fetuses A. Smolin 1 , M. Mazor 1 , E. Maymon 1 , A. Bashiri 1 , D. Dukler 1 , A. Bolotin 2 , A. Golan 1 , R. Hershkovitz 1 1 Soroka University Medical Center, Beer Sheva, Israel, 2 Ben Gurion University of the Negev, Beer Sheva, Israel Objective: This longitudinal study was designed to explore whether administration of betamethasone to preterm intrauterine growth restricted (IUGR) fetuses affects middle cerebral artery (MCA) blood flow velocimetry. Methods: Sixteen women (n = 16) with singleton preterm IUGR fetuses (below 10th percentile) were included. All patients were treated with a single course of betamethasone (12 mg qd I.M.) and were followed prospectively. Fetal MCA PI was recorded before, during first 4 days and 5–7 days after treatment. PI values were expressed according to the percentile of gestational age. A neonatal neurosonogram was performed during the first 72 hours of life. Descriptive statistics (mean and SD) and calculation (value after treatment minus the baseline) was used. Paired t-test on the equality of this to zero was than performed. Results: 1. The mean gestational age at admission and at delivery was 30.8 ± 2.4 weeks, and 32.9 ± 2.6 weeks, respectively. 2. The mean neonatal birth weight was 1492.8 ± 464.1 gr. 3. Value of MCA PI 4 days after treatment was −4.5 (95% CI −18.4; 9.2)(p = 0.4). 4. In contrast, value of MCA PI after 5 – 7 days was significantly different: 95% (−31.6 = CI −39.8; −23.4 p < 0.001;) 5. No pathological findings were demonstrated on neonatal neurosonogram. Conclusion: Betamethasone administration to preterm IUGR fetuses is associated with short term hemodynamic changes on the middle cerebral artery. OC24.07 Usefulness of measurement of the fetal thymus in the diagnosis of IUGR: a preliminary result J. Y. Cho , S. I. Jung, M. H. Moon, J. Y. Min, M. J. Song, J. A Kim, M. Y. Kim Samsung Cheil Hospital, Sungkyunkwan University School of Medicine, Republic of Korea Purpose: It is known that thymus is small in a growth-retarded baby. The purpose of this study is to assess the usefulness of the measurement of the fetal thymus in the diagnosis of intrauterine growth restriction (IUGR) of the fetus. Materials and methods: The maximum transverse diameter of the thymus was measured on prenatal ultrasound in 20 fetuses with expected weight smaller than 10 percentile of their gestational age. We compared the diameter with the reference value from 376 normal fetuses. We divided the fetuses into two groups according to the prenatal ultrasound, Doppler, biophysical profile, and postnatal findings; normal or constitutionally small group and 348 Ultrasound in Obstetrics & Gynecology 2005; 26: 309–375