Low β‐hCG is associated with poor prognosis in association with an embryo with positive cardiac activity

Seven pregnancies with positive fetal heart activity and low or very low serum β‐human chorionic gonadotropin (β‐hCG) levels were investigated. The gestational age by dates was between 6 weeks 3 days and 8 weeks 4 days at the time of the first ultrasound scan and β‐hCG ranged between 282 and 10 000 mIU/ml of the Second International Standard. The crown‐rump lengths ranged between 6 and 13 mm and heart activity was always detected. Four cases were scanned because β‐hCG was lower than that expected for the gestational age; in these cases the yolk sac was present but the gestational sacs were small, with a trophoblastic ring that looked thin and subjectively seemed abnormal. The β‐hCG level was measured in the other three cases, because the gestational sacs were small and had a thin trophoblastic ring. In these cases, fetal heart activity was clearly imaged. All cases were scheduled for a repeat ultrasound scan 2 weeks later. Three cases aborted spontaneously the following week, whereas in the other four no heart activity was detected in a repeat sonogram 2 weeks later. Low serum β‐hCG levels indicate a poor prognosis even when associated with an embryo with positive cardiac activity detected ultrasonographically. Copyright © 1995 International Society of Ultrasound in Obstetrics and Gynecology