Non-Invasive Prenatal Genetic Screening to Detect Trisomies In Singleton and Twin Pregnancies

Abstract

Background Screening for fetal anomalies is one of the most critical parts of prenatal testing to reduce the burden of chromosomal aberrations and improve clinical outcomes in pregnancy. The available literature suggests that India carries a strong economic, emotional, and health care burden of new-born genetic diseases. Material and Methods: We present a single-center retrospective study of 200 singletons and 6 dichorionic diamniotic twin gestations screened for chromosomal abnormalities and trisomies using NIPT.  The patients were presented with a gestation period of 10-12 (plus a few days) weeks, clinically confirmed with singleton or diamniotic dizygotic twins, who underwent NIPT between the years 2021-2022 (mid) at our center. All the patients underwent sonographic examination and biochemical investigations with regular follow-up and genetic counseling. The clinical history and family history of the presence of any genetic disease or any other disease were previously taken by the clinician in all cases. The main clinical indications were increased risk of trisomies found in markers test, advanced maternal age, or presented with some mild complications in pregnancy. Results; Out of the total (206) pregnancies, only 2 singleton cases were found at high risk in NIPT screen, prospectively followed up, and showed normal twins in six cases of twin pregnancy growing successfully. The high-risk cases were genetically counselled and further tests using amniotic or chorionic villi samples were recommended by the clinician with regular clinical follow-up. Conclusion: This retrospective study clearly indicates that non-invasive prenatal testing in pregnancy is a safe and effective screening test to rule out certain chromosomal abnormalities and to omit the need of further invasive tests among low-risk cases.