Quantifying the risk of ectopic pregnancy with a transient diagnosis of pregnancy of unknown location

Abstract

Objective: To quantify the risk of ectopic pregnancy among a transient diagnosis of pregnancy of unknown location (PUL). Methods: Retrospective cohort study between August 2016 and November 2020. The final cohort included 244 patients with 255 PULs who presented with vaginal bleeding and/or abdominal pain, positive serum quantitative β-human chorionic gonadotropin, and negative transvaginal ultrasound, with a subsequent definitive diagnosis. Two-way analysis of variance was used with significance set at P < 0.050. Bonferroni-corrected significance values were used in post hoc analysis. Multinominal logistic regression was used to predict adjusted risk for pregnancy outcome. Results: Definitive diagnosis consisted of 101 (39%) intrauterine pregnancies, 33 (13%) ectopic pregnancies, and 121 (48%) resolved PULs or resolved/treated persisting PULs. A total 68% of the PULs subsequently became nonviable. Vaginal bleeding was associated with increased risk of nonuterine pregnancies. Conclusion: A total of 13% of PULs were subsequently diagnosed as ectopic pregnancies, which is higher than the 2% to 3% risk of an ectopic pregnancy in the general reproductive population. A total of 68% of PULs were subsequently nonviable, which is higher than the 31% early pregnancy loss rate in the general reproductive population. This study quantitatively confirms that a transient diagnosis of a PUL increases the odds for ectopic pregnancy and early pregnancy loss.