hCG threshold predicts ectopic pregnancy treatment failure

An initial hCG level above 5,000 mIU/mL increases by almost five and a half times the odds of single-dose methotrexate failing to manage ectopic pregnancy, according to the findings of a systematic review.

Researchers analyzed five observational studies previously published on the topic including approximately 500 women to see if they could determine an hCG level threshold at which the odds of treatment failure greatly increased.

They determined that a substantial and statistically significant increase in failure rate is seen when women who have initial hCG levels >5,000 mIU/mL are compared with those who have initial levels <5,000 mIU/mL (OR 5.45; 95% CI, 3.04–9.78). Similarly, they calculated that women with an initial level between 5,000 and 9,999 mIU/mL are almost four times as likely to fail treatment as women with initial levels between 2,000 and 4,999 mIU/mL (OR 3.76; 95% CI, 1.16–12.33).

Menon S, Colins J, Barnhart KT. Establishing a human chorionic gonadotropin cutoff to guide methotrexate treatment of ectopic pregnancy: a systematic review. Fertil Steril. 2007;87:481-484.