Occult abnormal pregnancies after first post embryo transfer serum β hCG levels of 1 0 5 0 mIU mL

A first post–embryo transfer serum beta-human chorionic gonadotropin level of 1.0–5.0 mIU/mL may not exclude pregnancy and is associated with poor outcomes compared with a level <1.0 mIU/mL. Serial testing may be warranted. Authors:
Bat-Sheva L. Maslow, M.D., Alison Bartolucci, M.S., Carolina Sueldo, M.D., Lawrence Engmann, M.D., Claudio Benadiva, M.D., John C. Nulsen III, M.D.

Volume 105, Issue 4, Pages 938-945


To assess the occult pregnancy rate after “negative” first post−embryo transfer (ET) serum β-hCG results.

Two-part retrospective cohort study and nested case series.

University-based fertility center.

A total of 1,571 negative first post-ET serum β-hCG results were included in the study; 1,326 results (primary cohort, June 2009–December 2013) were initially reported as <5 mIU/mL and 245 results (secondary cohort, January 2014–March 2015) were reported as discrete values from 1.0 to 5.0 mIU/mL. Intervention(s):

Main Outcome Measure(s):
Rates of occult pregnancy, ectopic pregnancy, and complications after negative first post-ET serum β-hCG results.

A total of 88.8% (1,178/1,326) of the negative first post-ET results reported as <5 were <1.0 mIU/mL. Occult pregnancy was incidentally identified in 1.2% (12/1,041) of subjects with follow-up. Six had ectopic pregnancies, and seven experienced serious complications; 11 (91.7%) of the 12 occult pregnancies had a first post-ET serum β-hCG level of 1.0–5.0 mIU/mL and 1 (8.3%) <1.0 mIU/mL. All pregnancies with serious complications had initial β-hCG levels of 1.0–5.0 mIU/mL. Of the 245 results from after the policy change, occult pregnancies were diagnosed in 5.5% (9/163) of subjects with follow-up. One had an ectopic pregnancy, which was treated with methotrexate. There were no serious complications in the secondary cohort. Conclusion(s):
The majority of negative first post-ET serum β-hCG levels are <1.0 mIU/mL. Results from 1.0 to 5.0 mIU/mL may fail to exclude abnormal pregnancy and are associated with poor outcomes compared with β-hCG levels <1.0 mIU/mL. Serial serum β-hCG may be warranted in this population.

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