P25.10: Microdeletion and microduplication detection based on whole genome sequencing

Objectives: To review the efficacy of early second trimester ultrasonography for detecting fetal structural abnormalities in a low risk population. Methods: Retrospective study of the ultrasonographic findings and outcome of all pregnancies in women scanned in 2010–2011. 3242 fetuses were scanned in the first trimester with Voluson Expert abdominal and transvaginal. 489 scans performed around 16 weeks, were selectioned because fetal abnormalities or unsatisfactory views, or extrafetal anomalies (uterus, placenta, cord or amniotic fluid abnormalities). Main outcome: correlation of prenatal ultrasonografic findings with outcome in the neonate Results: 3215 babies were born during 2010–2011, 489 (15%) were scanned in early second trimester, 158 because fetal reasons and 331 because of extrafetal causes. In the group of fetal reasons, 27 fetuses (17,7.5%) were found to have serious abnormalities at birth or after termination of pregnancy. There were 2 spontaneous miscarriage and 16 therapeutic abortion before 18 weeks. In the group of extrafetal causes, 36 umbilical single artery were found, and others findings, irrelevant to the outcome in the neonate. Two false positive diagnoses occurred, in both cases the pregnancies were not terminated and the babies were born. This gives a specificity of 99.1% (78.2% to 99.7%). The positive predictive value of early second trimester ultrasonography was 98.1% (91.3% to 99.7%). Conclusions: Fetal examination by ultrasonography in early second trimester, in low risk population, detects many fetal abnormalities but can present 5% work overload.