Research Article: Incremental diagnostic value of serum progesterone combined with transvaginal ultrasound in differentiating early ectopic pregnancy: a single-center real-world study
Abstract:
To evaluate serum progesterone combined with transvaginal ultrasound for distinguishing ectopic pregnancy (EP) in patients with pregnancy of unknown location (PUL), and to assess diagnostic efficacy across risk stratifications.
Internally unvalidated analysis included 148 PUL patients (January 2022–December 2025). Final diagnosis by surgical pathology or follow-up divided patients into EP (49) and non-EP (99; intrauterine pregnancy or natural regression). All underwent initial transvaginal ultrasound to confirm PUL. The prediction point was the 48-hour reassessment. Predictors were abnormal adnexal findings on follow-up ultrasound at 48?h, serum progesterone, and 48-hour ? -hCG results available at that visit. The intended application is risk re-stratification and follow-up planning at 48-hour reassessment, not replacement of surgical/histopathological diagnosis or immediate treatment. Progesterone and ? -hCG were measured; groups were compared. Logistic regression screened independent predictors. ROC curves evaluated single and combined indicators. We assessed if progesterone improved the ultrasound?+?M6NP model, with M6NP defined as M6 excluding initial progesterone.
The EP group had lower serum progesterone, initial ? -hCG, 48-hour ? -hCG change rate, and endometrial thickness, and higher abnormal adnexal ultrasound detection ( P <?0.05). Multivariate analysis showed log progesterone, abnormal adnexal ultrasound, previous EP, and M6NP high-risk classification (?5%) were independent predictors ( P <?0.05). All AUC values are apparent/in-sample estimates. Ultrasound?+?M6NP had an apparent AUC of 0.913; adding progesterone increased it to 0.947. In the M6NP high-risk subgroup, progesterone plus ultrasound had an apparent AUC of 0.945 and specificity of 91.67%. Because the model was developed and evaluated in the same dataset without bootstrap or internal validation, estimates are preliminary and require external validation.
Internally unvalidated analysis, serum progesterone combined with transvaginal ultrasound was associated with improved apparent diagnostic accuracy for EP in PUL, especially within M6NP risk stratification. These estimates are apparent/in-sample, preliminary, and hypothesis-generating.
Introduction:
Ectopic pregnancy (EP) refers to the implantation of a fertilized egg outside the uterine cavity, with tubal pregnancy being the most common, accounting for over 95% of all EP cases ( 1 , 2 ). EP is one of the major causes of early pregnancy mortality, and early diagnosis and intervention are crucial for reducing maternal mortality and preserving fertility ( 3 ). In recent years, with the widespread application of assisted reproductive technology (ART), the incidence rate of EP is on the rise. It has been reported…
Read more