Active management of severe IUGR with AREDF in the umbilical artery seems beneficial. Survival rates with SLPCV were similar in s-IUGR and TTTS3D. However, there was a trend for higher survival rates in the AGA twin for CC. The choice of the technique should be driven by objective counseling on survival of both IUGR and AGA twins and therefore by the utility-based ethical values expressed by the pregnant woman.

BACKGROUND: Corpus callosum malformation (CCM) is the most frequent brain malformation observed at birth. Because CCM is a highly heterogeneous condition, the prognosis of fetuses diagnosed prenatally remains uncertain, making prenatal counseling difficult. METHODS AND RESULTS: We evaluated retrospectively a total of 138 fetuses, 117 with CCM observed on prenatal imaging examination, and 21 after postmortem autopsy. On ultrasound and/or magnetic resonance imaging, CCM was either isolated (N 5 40) or associated with other neurological (N 5 57) or extra cerebral findings (N 5 21/20, respectively). RESULTS: Most fetuses (N 5 132) remained without a diagnosis at the time of pregnancy termination. This emphasizes the need to establish a neuropathological classification and to perform a genomic screening using comparative genomic hybridization. A neuropathological examination performed on 138 cases revealed a spectrum of CCMs, classified as follows: agenesis of corpus callosum (55), CC hypoplasia (30), CC dysmorphism (24), and CCM associated with a malformation of cortical development (29). Of interest, after fetopathological examination, only 16/40 malformations were classified as isolated, highlighting the importance of the autopsy following termination of pregnancy. Among the 138 cases, the underlying etiology was found in 46 cases: diabetes (one case), cytomegalovirus infection (one case), 23 chromosome abnormalities, and 21 mendelian conditions. CONCLUSION: In our series of 138 cases of CCM, prenatal and postmortem examinations identified a variety of genetic causes. However, no diagnosis could be established in 67% of cases. The classification based on the underlying neurodevelopmental defects paves the way for further genetic studies and genotype-phenotype correlations.

22nd World Congress on Ultrasound in Obstetrics and GynecologyPoster abstracts acardiac twin was performed. Under fetoscopic observation, the cord was resected by scissors which inserted through operating channel in fetoscope. The patient delivered a 2290 g, female infant at 32 weeks of gestation after spontaneous rupture of membrane. Gross specimen of the placenta and acardiac twin showed complete obstruction of the anastomoses and no cord entanglement. P09.22Perinatal outcomes following radiofrequency ablation in monochorionic pregnancies Results: 84 cases of RFA were performed (31 for structural anomaly, 9 for TRAP, 20 for TTTS, 2 for aneuploidy, 11 for MFPR, 11 for FGR). The median gestation at RFA was 17.5 weeks (range 12.1-27.6 weeks). The overall live birth rate was 82%. PPROM and/or miscarriage within 2 weeks occurred in 3% of cases respectively. Co-twin IUD occurred in 13% of cases. The median gestation at delivery was 35 weeks (Range 14-41 weeks). The preterm (< 37 weeks) live birth rate was 45%. The incidence of brain injury following the RFA was 4.5%. Neonatal death occurred in 1.2% of cases. The incidence of co-twin demise appeared greatest (19.2%) when the RFA was performed before 16 weeks compared to after 16 weeks (13.9%), although this did not reach significance (P = 0.082). There were no maternal complications. Conclusions: RFA is a safe technique for selective reduction in MC pregnancies and can be performed much earlier compared with other methods. The risk of co-twin demise appears greatest before 16 weeks gestation. P09.23A clinical trial of ultrasound treatment for TRAP sequence We present a case of TRAP sequence for which high-intensity focused ultrasound (HIFU) was applied as a non-invasive fetal therapy. Case; A 23-year-old woman was admitted to our hospital at 22 gestational weeks. Ultrasonography led to a diagnosis of TRAP sequence. Neither hydramnios nor signs of heart failure were identified in the normal fetus, but because the anomalous fetus displayed pronounced subcutaneous edema, the decision was made at 26 gestational week to apply ultrasound-guided HIFU exposure to occlude the vessel and interrupt the blood flow of the anomalous fetus. The Ethics Committee for Clinical Studies approved the procedure and consent was obtained from the patient after explanation. Target for HIFU exposure was the internal blood flow at the point where the umbilical cord entered the body of the anomalous fetus. Exposure was performed multiple times and decreased blood flow was confirmed by Doppler color imaging; however, complete occlusion was not achieved. Despite the failure of complete occlusion, a hyperechoic area was observed just proximal to the target blood; this finding indicated degeneration of the tissue by exposure to HIFU. Collateral damage was not seen in either the pump fetus or the mother's body. Polyhydramnios appeared at 29 gestational weeks, thus making premature birth an imminent threat. Therefore, a cesarean section was performed. The pump fetus weighed 845 g, the anomalous fetus...