SUMMARYThis study uses current epidemiological data to evaluate whether phytoestrogen intake is associated with a reduced risk of prostate cancer. We performed a random-effect meta-analysis of published data retrieved from PubMed, Web of Science, ProQuest, and CNKI, which was supplemented by a manual search of relevant references. Study quality was assessed using the Newcastle-Ottawa Scale (NOS). Subgroup analysis and meta-regression were performed to explore the source of heterogeneity. Sensitivity analysis was evaluated to assess the stability of the results. Egger's test and funnel plots were used to detect the existence of publication bias. We retrieved 507 papers, and 29 studies were ultimately confirmed as eligible. The meta-analysis showed that phytoestrogen intake was significantly associated with a reduced risk of prostate cancer, with an odds ratio (OR) of 0.77 (95% CI 0.66-0.88; I 2 = 77.6%). The food/nutritional sources that were significantly associated with a reduced risk of prostate cancer included soy and soy products, tofu, legumes, daidzein, and genistein. Subgroup analysis indicated that the associations were significant among Asians and Caucasians, but not among Africans. Meta-regression revealed that the pooled OR increased with the number of cases in the studies. The results might be affected by publication bias based on the Eggers' test (p = 0.011) and the asymmetry of the funnel plot. Phytoestrogen intake may reduce the risk of prostate cancer in Asians and Caucasians. Regular intake of food that is rich in phytoestrogens, such as soy/soy products or legumes, should be recommended.

Virtual poster abstracts Methods: Case note review of all cases from May 2014-October 2019. Results: FLA for TTTS was performed in 46 women at 16-26 weeks gestation. The median Quintero stage at FLA was II. 38 women underwent fetal neurological MRI assessment subsequent to their laser therapy and eight women did not undergo fMRI (three patients had an intrauterine loss of both fetuses; four patients delivered prior to planned fMRI and one patient declined fMRI). Of the 38 women undertaking MRI assessments: 25 had two surviving fetuses and 12 had one surviving fetus, with a total of 63 fetuses assessed. The fMRI was performed at a median gestation 26 weeks (range 23-30 weeks) post-FLA. fMRI demonstrated macroscopic brain abnormalities in 6% (4) of imaged fetuses: mild ventriculomegally (1), reparative microgyria (2) and small volume germinal matrix bleed (1). These were likely to be sequelae of TTTS plus or minus its therapy by FLA. Conclusions: 6% of fetuses assessed by interval fetal MRI had evidence of macroscopic neurological findings on fMRI. This data supports the known literature of neurological sequelae of TTTS and antenatal imaging of these babies has allowed for tailored neurodevelopment follow-up. VP43.02 Predictive value of twins' umbilical intercord distance for complications in monochorionic twin pregnancy

Objectives: Echogenic and/or dilated bowel is often encountered on prenatal ultrasound and may represent a feature of gastrointestinal pathology, chromosomal abnormality or sign of prenatal infection. Prenatal differentiation between transient, physiological versus pathological manifestation is often difficult and remain uncertain. As a consequence, patients' counselling and timely involvement of pediatric surgeons is challenging. We aimed to review prenatal cases with echogenic or/and dilated bowel and analyse their neonatal outcomes. Methods: This is a retrospective observational study. All ultrasound scans demonstrating fetal echogenic and/or dilated bowel were retrieved from the viewpoint and grouped into three categories: 1. echogenic; 2. dilated and 3. combined cases. Bowel echogenicity has been defined as grade 1 to 3, in relation to the surrounding liver or bone echogenicity. Bowel dilatation is defined as the largest diameter measuring >7mm during second and third trimester. Results: Out of 26,353 screened prenatal ultrasound scans: 30, 3 and 8 cases were identified with bowel echogenicity (grade 2 or 3), dilatation and their combination respectively. 9/41 (21%) neonates had confirmed gastrointestinal related pathologies; 5 with echogenic and 2 from each, dilated and combined bowel abnormalities group. 3/30 (10%) cases with echogenic and 1/8 (13%) case with dilated bowel required postnatal intestinal surgery. None among neonates with combined echogenic and dilated bowel exhibited structural intestinal abnormality that needed surgical correction. Conclusions: Prenatal diagnosis of isolated echogenic and/or dilated bowel carries overall favourable neonatal outcomes. However, still minority of cases with fetal echogenic or dilated bowel may elucidate of possible gastrointestinal abnormalities that require thorough parents' counselling, prenatal work up and multidisciplinary team involvement. Further research is needed to more precisely define prenatal ultrasound features of severe gastrointestinal abnormalities that require neonatal interventions. VP09.08 Cystic biliary atresia or choledochal cysts: is it possible to be accurately differentiated prenatally?

Conclusions: MC twins have significantly increased rates of fetal loss and perinatal mortality. The risk of cerebral damage in the surviving twin in MC pregnancies is high and procedures restrincting inter-twin transfusion reduce but do not totally prevent neurological damage.