Prenatal diagnosis of chromosomal abnormalities in a resource-poor setting
Objective: To compare the efficacy and efficiency of systematic, ultrasound-based risk adjustment using a published algorithm with that of a maternal age cutoff of 37 years for the prenatal detection of chromosomal abnormalities (especially autosomal trisomies). Methods: These approaches were compared in a retrospective study of 136 chromosomal abnormalities confirmed by karyotyping prenatally (n = 46) or postnatally (n = 90). There were 114 autosomal trisomies. Results: Maternal age was known for 103 fetuses with confirmed abnormalities. The ultrasound-based risk adjustment approach was more sensitive for autosomal trisomy (93.9% vs 44.1%), and karyotyping for younger women with abnormalities on ultrasound was more effective than routine karyotyping in older women (1 trisomy detected in 13.5 vs 42.8 samples, P < 0.001). A lack of screening was the main reason for the postnatal diagnosis. Conclusion: Ultrasound-based risk adjustment was the more effective approach. © 2008 International Federation of Gynecology and Obstetrics.