Screening for fetal anomalies in 11 to 13 weeks Ultrasonogram: A Prospective study

SUMMARY: This study was chosen to detect the incidence of major fetal abnormalities in general obstetric population and to evaluate the performance of ultrasonogram screening during 11 to 13 weeks gestation. 284 antenatal mother were screened for fetal anomalies in a two stage ultrasound scanning at 11 to 13 weeks gestation and follow up scan at 18 -22 weeks. • The incidence of major fetal abnormalities was 3.2%. • The sensitivity of first trimester (11-13 wks ) scan in detecting the anomalies was 33% in this study. • The overall sensitivity of ultrasonogram in detecting the anomalies was 100%. • Increased nuchal translucency measurement was detected in two cases. • 3 cases of missed abortion was detected at the time of 11-13 weeks scan which was an incidental finding. • Craniospinal abnormalites were the most common abnormalities detected and hence it indicates the need for periconceptional folic acid intake. CONCLUSION: 1. The detection of the major anomalies at this early gestation (11-13 wks) offers to the parents the option of an earlier, safer and psychologically less traumatic termination of the pregnancy. 2. The ultrasound examination at 11-14 wks to screen for fetal abnormalities is effective and can be an adjunct to the routine 18-22 weeks anomaly scan. 3. Hence first trimester ultrasound (11-13wks) must be made mandatory, not only for the detection of major fetal anomalies, but also for diagnosing multiple pregnancy and abnormal pregnancy like missed abortion, molar pregnancy and ectopic pregnancy