Purpose: To correlate sonographic findings of fetal developmental abnormalities resulting from chromosomal aberrations and structural anomalies in 2nd trimester. Design: Cross-sectional study. Setting: Tertiary care centre.
Patients and Methods: Amid the reporting period from August 2007 to July 2014, prenatal fetal anomaly diagnosis in 9524 fetuses/babies were inspected and contrasted with post-natal diagnosis.
Results: Overall, 233 fetuses/babies had affirmed anomalies, prevalence 2.45%. Out of those fetuses/ babies, 22.31% (52/233) had chromosomal anomalies, prevalence 0.55%, and 78% (181/233) had ordinary chromosomes along with structural anomalies (major (43.64%; 79/181) and minor (56.35%; 102/181)), prevalence 1.9%. The affirmed anomalies distinguished prenatally were 102, giving a total sensitivity for prenatal fetal anomaly detection of 43.78% (102/233; 95% Confidence Interval (CI) 37.31-49.98), specificity of 99.95%, PPV of 95.33% and NPV of 98.61%. The aggregate detection rate prior to 22 gestation weeks was 40.34% (94/233; 95% CI 33.99-46.95). The pre-natal detection rate of chromosomal anomalies was 61.5% (32/52) and for structural anomalies, 38.7% (70/181).
Conclusion: In a routine clinical setting at a hospital, half of major structural anomalies in fetuses with normal chromosomes are identified by standard ultrasound exam in 2nd trimester. Chromosomal anomalies have the greatest probability for prenatal detection; the greater part is diagnosed by amniocentesis prior to standard ultrasound exam in high-risk women.