Progesterone as a Prognostic Biomarker for Expectant Management of Tubal Ectopic Pregnancy: A Narrative Review

Background/Objectives: Tubal ectopic pregnancy (TEP) remains a significant cause of maternal morbidity and mortality. Early access to pregnancy assessment units now allows for the detection of many TEPs at a stage at which they could potentially resolve spontaneously. The current selection of women for expectant management is guided by human chorionic gonadotrophin (hCG) concentrations, alongside ultrasonographic and clinical features, although reported success rates vary widely in the literature. We evaluated whether progesterone, another biomarker secreted during pregnancy, can predict successful expectant management alone or in combination with hCG. Methods: A narrative review was undertaken using Ovid MEDLINE and Embase, searched from 1 January 1990 to 1 May 2026, with a supplementary grey literature search. Of 1363 records identified, 27 studies were included. Results: Progesterone is associated with pregnancy viability but performs poorly in isolation for distinguishing ectopic from non-ectopic pregnancy. However, in studies of expectant management success, it has been identified as a second-tier variable that may improve prediction of successful expectant management of TEP. Conclusions: Current evidence does not support the use of progesterone as an independent predictor of expectant management success. It may provide additional prognostic information within an hCG-defined stratum, but this requires further validation before implementation in clinical practice.