143: Ultrasound at 11-14 weeks: “Nuchal scan” or “early anatomy scan”?

Abstract

ObjectiveOur objective was to identify the rate of structural fetal anomalies identified at 11-14 weeks in patients referred for NT measurement.Study designRecords of all women referred for first-trimester risk assessment from 1/2003-7/2007 were reviewed. In our ultrasound unit, early survey of fetal anatomy is always performed at the time NT is measured. Cases in which ultrasound was diagnostic for structural fetal anomalies were identified. Cystic hygroma/abnormal NT were not considered structural anomalies. Outcomes were identified by medical record review.ResultsDuring the study period, 15,319 pregnancies with 15,910 fetuses were referred for risk assessment. Structural abnormalities were identified in 29 fetuses, at a rate of 1 in 528 pregnancies. The types of abnormalities identified are listed in the Table. NT was normal in 4 of 9 fetuses with an abnormal karyotype. In most cases, detection of a structural abnormality led to early abortion.Tabled 1Fetal anomalies diagnosed at 11–14 weeksAnomalyNumberAbnormal KaryotypeAbortionAnencephaly or Acrania918Holopros-encephaly323Cephalocele202Omphalocele867Gastroschisis200Limb Reduction100Amniotic Band Syndrome404TOTAL299 (31%)24 (83%) Open table in a new tab ConclusionEvaluation of fetal anatomy at the time NT is measured will identify certain structural abnormalities in the first-trimester, and clearly enhances the value of first-trimester risk assessment. This important benefit must be considered when implementing protocols for aneuploidy risk assessment. ObjectiveOur objective was to identify the rate of structural fetal anomalies identified at 11-14 weeks in patients referred for NT measurement. Our objective was to identify the rate of structural fetal anomalies identified at 11-14 weeks in patients referred for NT measurement. Study designRecords of all women referred for first-trimester risk assessment from 1/2003-7/2007 were reviewed. In our ultrasound unit, early survey of fetal anatomy is always performed at the time NT is measured. Cases in which ultrasound was diagnostic for structural fetal anomalies were identified. Cystic hygroma/abnormal NT were not considered structural anomalies. Outcomes were identified by medical record review. Records of all women referred for first-trimester risk assessment from 1/2003-7/2007 were reviewed. In our ultrasound unit, early survey of fetal anatomy is always performed at the time NT is measured. Cases in which ultrasound was diagnostic for structural fetal anomalies were identified. Cystic hygroma/abnormal NT were not considered structural anomalies. Outcomes were identified by medical record review. ResultsDuring the study period, 15,319 pregnancies with 15,910 fetuses were referred for risk assessment. Structural abnormalities were identified in 29 fetuses, at a rate of 1 in 528 pregnancies. The types of abnormalities identified are listed in the Table. NT was normal in 4 of 9 fetuses with an abnormal karyotype. In most cases, detection of a structural abnormality led to early abortion.Tabled 1Fetal anomalies diagnosed at 11–14 weeksAnomalyNumberAbnormal KaryotypeAbortionAnencephaly or Acrania918Holopros-encephaly323Cephalocele202Omphalocele867Gastroschisis200Limb Reduction100Amniotic Band Syndrome404TOTAL299 (31%)24 (83%) Open table in a new tab During the study period, 15,319 pregnancies with 15,910 fetuses were referred for risk assessment. Structural abnormalities were identified in 29 fetuses, at a rate of 1 in 528 pregnancies. The types of abnormalities identified are listed in the Table. NT was normal in 4 of 9 fetuses with an abnormal karyotype. In most cases, detection of a structural abnormality led to early abortion. ConclusionEvaluation of fetal anatomy at the time NT is measured will identify certain structural abnormalities in the first-trimester, and clearly enhances the value of first-trimester risk assessment. This important benefit must be considered when implementing protocols for aneuploidy risk assessment. Evaluation of fetal anatomy at the time NT is measured will identify certain structural abnormalities in the first-trimester, and clearly enhances the value of first-trimester risk assessment. This important benefit must be considered when implementing protocols for aneuploidy risk assessment.