Prenatal Aneuploidy Screening and Diagnosis—Its Evolution and Trends: A 3-year Analysis in a Fetal Medicine Center

Abstract

Introduction: After the ACOG guideline in 2007 recommending that all women, regardless of age, should be offered aneuploidy screening before 20 weeks of gestation. This protocol in the name of the fetal aneuploidy screening program was slowly introduced in various Indian hospitals. This observational study was performed to analyze population-based trends of prenatal testing (serum screening and invasive testing) for aneuploidy over 3 years (2017)(2018)(2019). Materials and methods: A retrospective single-center study was carried over a period of 3 years (January 2017 to December 2019). This hospital was a tertiary care hospital with fetal medicine unit that had approximately 3,000 annual births. Analysis of data of all pregnant women undergoing prenatal testing before 20 weeks of gestation was collected in the following subheads: (1) aneuploidy screening data, (2) invasive testing data [amniocenteses and chorionic villus samplings (CVSs)], and (3) tertiary care hospital birth statistics from January 2017 to December 2019. Results: Over a period of 3 years, aneuploidy screening was accepted by the target population and at present >85% target population undergo aneuploidy serum screening. Annual numbers of invasive prenatal tests climbed steadily from 2017 to 2019. The proportion of invasive testing performed for abnormal serum screening (ASS) increased steadily from 51% in 2017 to 72% (p < 0.05) in 2019. While the indications abnormal ultrasound finding (AUS) showed a steady decline over the same timeline but an indication of previous baby affected with aneuploidy (PBAA) remained in the same range. By 2019, the most common indications for invasive tests were positive ASS (72%) and AUS abnormality (15%). The diagnostic yield of all invasive tests for a major chromosome abnormality over a 3-year study period was 4.7%. The rate of CVS to amniocentesis rose to 17.5% in 2019 from 4.6% in 2017. Fewer complications of invasive tests were observed as compared to previous studies. Conclusion:The study demonstrates a rise in aneuploidy serum screening and its acceptance in the pregnant population. Abnormal serum screening is the main indication of prenatal invasive testing. This study also adds to the safety profile of invasive testing.