Abstract
INTRODUCTION: First-trimester ultrasound is widely accepted as part of standard care in many countries. With improvements in equipment, expertise and increasing number of technical studies describing imaging techniques, the detection rate for major fetal anomalies in the first trimester continues to rise and can be as high as 60% in high-risk populations. METHODS: We set out to create a systematic pictorial guide for trained ultrasound providers to describe the common anatomical structures that are identifiable in the first trimester with provided images. In addition to normal anatomical structures, a number of anomalies with high detection rates are listed. CONCLUSION: A large proportion of the major fetal abnormalities can be detected in the first trimester. A systematic approach is essential to ensure that anomalies are equally likely to be detected for patients of any risk background.