VP38.15: Etiology and outcome in anomalous late onset suspected fetal growth restriction

To investigate the etiology and perinatal outcome of suspected fetal growth restriction (FGR) diagnosed between 32+0–36+6 weeks and associated with structural defects, genetic anomalies or congenital infections. Retrospective multicentre study of singleton pregnancies seen at referral Fetal Medicine units, in which FGR was suspected between 32+0–36+6 weeks of gestation based on either abdominal circumference or estimated fetal weight < 10th percentile for gestational age or a reduction by over 50 percentiles from an ultrasound scan performed between 18–32 weeks of gestation. The study group included pregnancies with suspected late FGR associated with a genetic or structural anomaly or a congenital infection (anomalous FGR), while the control group consisted of structurally and genetically normal pregnancies with suspected late FGR (non-anomalous FGR). Results of genetic testing, TORCH screening and ultrasound findings, as well as perinatal outcome, were investigated. Of 509 pregnancies complicated by late FGR, 41 (8%) had anomalous FGR. Of these, 1 had congenital toxoplasmosis and 15 (41.7%) had minor anomalies, mainly affecting the male genitalia. Such cases were not considered for outcome comparison. Of the remaining 25 anomalous FGR fetuses, a confirmed genetic abnormality accounted for 4/25 cases (16%). The most common structural defects associated with suspected late FGR were limb abnormalities (11/21, 52%). 1 case of stillbirth was recorded in the non-anomalous FGR group. No differences were noted in terms of perinatal survival and outcome between pregnancies with anomalous and those with non-anomalous late FGR, with the only exception of NICU admission which was recorded in 9/25 (36%) anomalous FGR and in 73/468 (15.6%) non-anomalous FGR (p < 0.01). The perinatal survival and outcome is not dissimilar between anomalous and non-anomalous FGR diagnosed between 32+0–36+6 weeks of gestation.