The early pregnancy ontology contains the concepts to describe ectopic pregnancy ultrasound images, organized into several subsumption hierarchies for types of ectopic pregnancies and the signs, anatomical structures and technical elements of imaging associated with ectopic pregnancy. Version 1.1 was used for ultrasound image annotations (Dhombres et al. Developing a knowledge base to support the annotation of ultrasound images of ectopic pregnancy. J Biomed Semantics, 2017)