Is There a Role for Hyperglycosylated hCG in the Diagnosis of Ectopic Pregnancy in Women with a Pregnancy of Unknown Location?

Abstract

OBJECTIVE: To examine the potential use of hyperglycosylated human gonadotropin (hCG-H) in identifying ectopic pregnancies in pregnancies of unknown location (PULs) on ultrasound scan. STUDY DESIGN: This was a prospective observational study. An additional blood sample was taken from women whose initial transvaginal ultrasound scan showed none of the following: intact intrauterine pregnancy, retained placental tissue, or ectopic pregnancy. Parallel sandwich ELISAs were performed using sheep monoclonal antibodies to the 12F6 epitope for detection of total hCG and to the 4D8 epitope for hCG-H detection, and an automated immunoassay technique was used for progesterone and serum β-hCG measurements. Patients were managed accord-ing to our standard clinical protocol. RESULTS: hCG-H was significantly higher in ectopic pregnancies (85.6 ng/mL) than in viable intrauterine pregnancies (26.8 ng/mL) and spontaneously resolving pregnancies (23.2 ng/mL). The ability to distinguish ectopic pregnancies from nonectopic pregnancies, expressed as area under the curve, was 0.816 for hCG-H and 0.824 for total hCG. CONCLUSION: Women with an underlying ectopic pregnancy tended to have higher hCGs, whichever assay was used. However, the current study does not support a role for a single measurement of hCG-H in the diagnosis of ectopic pregnancy within the PUL population.