Diagnostic Criteria for Nonviable Pregnancy Early in the First Trimester

This review from the Society of Radiologists in Ultrasound outlines evidence-based criteria for diagnosing nonviable pregnancy in the early first trimester using ultrasound and serum hCG measurements. It recommends stricter thresholds, such as a crown-rump length of 7 mm or greater without cardiac activity or a gestational sac of 25 mm or greater without an embryo, to reduce false-positive diagnoses. The article stresses careful interpretation and follow-up so that potentially viable pregnancies are not ended unnecessarily.