First Trimester Anomaly Scan

Abstract

The goal of pregnancy ultrasound scans during the first trimester is to provide accurate information for optimised antenatal care, ensuring the best outcomes for both mother and foetus. Divided into early and late stages, early scans between 6 to 8 weeks focus on determining gestational sac implantation, viability and identifying multiple pregnancies. First-trimester screening, conducted at 11 + 0 to 13 + 6 weeks, includes biometry, anomaly scan, chromosomal abnormality assesment and screening for pre-eclampsia through maternal serum biochemistry. This pictorial essay emphasises the importance of a systematic examination of foetal anatomy during first-trimester screening, aiding in the early detection of structural anomalies. The protocol-based approach ensures reliability in detecting or ruling out abnormalities, allowing for timely counselling and further testing if necessary. While both transabdominal and transvaginal approaches may be utilised, the latter may offer better resolution, especially in certain patient populations. Despite limitations, a comprehensive first-trimester anomaly scan serves as a crucial tool in detecting major foetal abnormalities and providing reassurance to expecting mothers.