P047: Look beyond crown rump length

Abstract

Due to better quality ultrasound machines with improved resolution, numerous structural congenital abnormalities have been reported in first trimester. Early detection of fetal structural and chromosomal abnormalities and indexes of increased risk of chromosomal abnormalities may reduce maternal anxiety, and allow early termination of pregnancy, or better timing for invasive procedures. The study was performed between 1.9.2000 and 30.12.2002 at Princess Margaret Hospital, Hong Kong. All women attending the Prenatal Diagnostic Clinic between 10–14 weeks were included. The perinatal outcomes of the above pregnancies were traced and reviewed. First trimester screening for nuchal translucency and structural abnormality was performed for all women referred for Prenatal Counseling. A total of 1134 pregnancies were assessed between 10 + 4 − 14 weeks of gestation. A total of 21 fetuses (1.9%) with fetal abnormalities were detected. These included chromosomal abnormalities such as Down syndrome, Edward syndrome, Patau syndrome and Turner syndrome. Congenital structural abnormalities detected including amniotic band syndrome, ectopic cordis, omphalocoele, gastrochisis, acrania, fixed flexion of the wrists, hypoplastic/absence of radius, cystic hygroma, bilateral pleural effusion, megacystis, hypoplastic nasal bone and syndactyly. A case of fetal bradycardia due to atrial ectopic beats was also detected during the study period. Though, there were a number of fetal structural abnormalities, which were not detected prior to 14 weeks in this cohort. These include partial sacral agenesis, cleft lip and palate, ventricular septal defect, atrial septal defect, partial atrio-ventricular septal defect, and polydactyly. Second trimester soft signs for Down syndrome did not usually present in first trimester. Women seek prenatal diagnosis should be offered early ultrasound screening which include screening for major structural abnormality and nuchal translucency assessment and screening for major structural abnormality.