7–11 October 2007, Florence, Italy Oral poster abstracts SD); 1.10 (0.46) vs. 0.86 (0.34) (P = 0.019), and 0.58 (0.15) vs. 0.47 (0.095) (P = 0.001), respectively. When data were analyzed according to the stages of severity, recipients and donors from TTTS Grade 2 showed a significantly higher DVPI than TTTS Grade 1 (1.30 (0.49) vs. 0.86 (0.28) (P = 0.003), and 0.99 (0.38) vs. 0.71 (0.22) (P = 0.011), respectively). Despite the fact that differences did not reach statistical significance, Mod-MPI showed the same trend only in recipients (0.61 (0.16) in Grade 2 vs. 0.54 (0.13) in Grade 1, P = 0.1). Conclusions: Fetal cardiac function, assessed by increased DVPI and Mod-MPI, is impaired in TTTS, especially in recipient fetuses. These alterations seem to be related to the degree of severity according to Quintero stage. OP10.04 Outcomes in a cohort of patients with stage 1 twin–twin transfusion syndrome M. W. Bebbington , E. Tiblad, R. D. Wilson, S. E. Mann, M. Huesler-Charles, M. P. Johnson Center for Fetal Diagnosis and Treatment, Children’s Hospital of Philadelphia, United States Objectives: To determine pregnancy outcome of patients who present with Stage 1 TTTS at a single center. Methods: A retrospective review of all patients with TTTS between January 2005 and December 2006. Quintero criteria were used for staging. Laser ablation was not offered to patients with stage 1 disease. Results: A total of 155 twin pregnancies were evaluated for TTTS during this period. Of those, eight were normal, 47 had another diagnosis, and 58 were TTTS at stage 2 or above. The remaining 42 were included in the analysis. The overall survival was 84%. The mean gestational age at the time of consultation was 20.9 ± 0.4 weeks. A total of 22 cases underwent amnioreduction (AR), 13 prior to consultation, seven at the time of consultation and two after being returned to their referring practitioner. There was no difference in the mean AFI at consultation between those with a prior AR and those without (23.2 ± 3.0 vs. 24.3 ± 1.2, P = 0.73). Progression of TTTS, requiring invasive therapy (laser/cord cautery) occurred in four cases, all of which had had an AR at the time of consultation. One patient self-referred for invasive therapy elsewhere. Excluding these five patients, the mean gestational age at delivery was 31.0 ± 0.83 weeks for those who had AR vs. 32.6 ± 1.0 weeks for those who did not (P = 0.22). The mean birth weight for donors was 1360 ± 175 g vs. 1745 ± 135 g(P = 0.09) and for recipients it was 1672 ± 164 g vs. 2027 ± 189 g(P = 0.17). Conclusions: In those cases where AR was not required, no cases showed progression of their TTTS. Among those where AR was used, progression occurred in only 17% of cases. The mean gestational age at delivery of this cohort does not differ from those patients treated at our institution for more advanced stages of TTTS with placental laser ablation. Overall outcomes in Stage 1 TTTS do not seem to be improved significantly by the use of AR, but the small numbers indicate the need for more study. OP10.05 Ultrasonographic evidence of brain lesion in surviving monochorionic twin after in utero death of co-twin A. Pintucci 1 , M. Lanna 2 , M. A. Rustico 2 , A. Righini 2 , C. Parazzini 2 , U. Nicolini 2 1 Policlinico di Bari, Italy, 2 P. O. V. Buzzi Milano, Italy Objectives: To evaluate fetal neurosonographic findings, compared with prenatal MRI ones, in cases of MC twin pregnancies, complicated by spontaneous or iatrogenic IUFD of the co-twin. Methods: A review of MC pregnancies referred to our unit. Complicated MC pregnancies were: Group 1 with twin–twin transfusion syndrome (TTTS), Group 2 with intrauterine growth restriction (IUGR) and absent or reversed end-diastolic flow (AREDF) in umbilical artery of one fetus, and Group 3 with discordant anomaly. For Group 1, endoscopic laser coagulation of the communicating vessel on the chorionic plate (ESLCV) or serial amniodrainage (AD) or cord occlusion (CO) of one twin was performed; for Group 2 or 3 CO of one twin was the only treatment. In all cases complicated by IUFD of one twin, neurosonography followed by fetal MRI was performed. Results: Between 2001 and 2006, 401 MC twin pregnancies were observed. Among these, 167 (41%) were in Group 1, 45 (11%) were in Group 2, and 56 (14%) were in Group 3. In Group 1, 73 pregnancies (43.7%) were treated with ESLCV, 39 (23.3%) with AD, 28 (16.7%) with CO. In Group 2, 13 pregnancies (28.8%) were treated with CO. In Group 3, 24 pregnancies (43%) were treated with CO. There was spontaneous death of one twin in 13 cases (3.2%). Mean gestational age (GA) at time of IUFD was 21.9 ± 3.59 after ESLCV and 22.1 ± 4.75 when spontaneous. When severe brain lesions were observed in the surviving twin, mean GA of IUFD was 20.4 ± 2.46. There were severe brain lesions in two of 25 cases of IUFD of one twin after ESLCV (8%), and in seven of 13 cases (54%) of spontaneous IUFD. Brain findings were intra-ventricular hemorrhage (one), sub-acute ischemia (three), chronic ischemic sequelae (two) with associated polimicrogyria (one), periventricular leukomalacia (one), and undefinite parenchyma damage (two). The pregnancy was terminated in seven cases. The remaining two twins were born, with 1 year neurological follow-up. Conclusions: Severe brain lesions in surviving twin were more frequent in spontaneous IUFD. OP10.06 Prenatal imaging and neurological follow-up in the survivors of monochorionic twin pregnancies with a single intrauterine death A. Fichera , C. Zambolo, S. Andrico, C. Ambrosi, R. Gasparotti, P. Accorsi, P. Martelli, A. Pelis, T. Frusca University of Brescia, Italy Objectives: To assess the outcome and neurological follow-up of the co-twins of monochorionic twin pregnancies with a single intrauterine death evaluated with prenatal ultrasound and magnetic resonance after the diagnosis of death. Methods: Thirteen monochorionic twin pregnancies with a single intrauterine demise were identified. Serial scans after the diagnosis of a single death were performed and, in addition, seven patients underwent prenatal MRI in order to identify the presence of cerebral lesions in the survivors. Postnatal cranial scans and results of neurological follow-up were recorded and analyzed in relation to the prenatal findings. Results: Median gestational age at the diagnosis of single fetal death was 24.3 (range, 17–32.2) weeks. Perinatal survival rate of the co- twin was 86% (11/13). MRI scans were performed at a median gestational age of 20.6 (range, 19.1–31.5) weeks. Mean latency between the diagnosis of single fetal death and the MRI scan was 15 ± 6.1 days. In all cases there were no signs of ischemic brain lesions in the survivors at the diagnosis of single death, during ultrasonographic follow-up or at MRI. One case was complicated by intrauterine death of the co-twin after 6 days (at 25 weeks) and in one case, delivered at 28 weeks for abnormal CTG immediately after the diagnosis of single death, IVH was evident at postnatal cranial scan, and the newborn died 3 days after birth. In both cases no sonographic signs of brain lesions were present and prenatal MRI was not performed. Cranial scans performed after birth did not show any abnormalities and no neurological sequelae were observed at the follow-up (mean time 17.5 ± 10.1 months) in any surviving infants. Conclusions: In monochorionic twin pregnancies ultrasound examination of the fetal brain of the twin survivor at the diagnosis of single intrauterine death can be normal, as it can also be in fetuses with successive evidence of cerebral lesions. Normal sonographic Ultrasound in Obstetrics & Gynecology 2007; 30: 456–546 487