The performances of serum activins and follistatin in the diagnosis of ectopic pregnancy: A prospective case-control study.

Background: The diagnosis of ectopic pregnancy (EP) is challenging and 40-50% of patients are initially misdiagnosed.

Methods: This prospective case-control study measured activin-A, activin-B, activin-AB and follistatin for the diagnosis of EP, spontaneous abortion (SAB) and normal intrauterine pregnancy (IUP). Sera were collected from 120 women with symptoms suggesting early pregnancy failure and who were clinically diagnosed as IUP, SAB or EP (n = 40/group). The markers were measured by ELISA and their area under the curve (AUC), cut-off value, sensitivity and specificity were determined by receiver-operating characteristic curve. The results were compared with serum β-human chorionic gonadotropin and progesterone.

Results: Activin-A and activin-B decreased significantly, while activin-AB and follistatin increased, in the EP and SAB groups than the IUP group. Activin-AB (AUC = 0.961) and progesterone (AUC = 0.973) were the best markers for EP and SAB, respectively. Activin-AB (≥61.5 pg/mL) showed 92.5% sensitivity, 85% specificity, 75.5% positive predictive value (PPV) and 95.8% negative predictive value (NPV) for EP. Progesterone (≤6.3 ng/mL) had 100% sensitivity, 86.2% specificity, 78.4% PPV and 100% NPV for SAB.

Conclusions: Serum activins and follistatin were significantly altered with EP and activin-AB could be a promising marker for the diagnosis of EP.