INTRODUCTION: Activin is necessary for maintaining normal pregnancy; follistatin and follistatin like 3 (FSTL3) are known antagonists of activin. FSTL3 also has a role in migration and invasion of trophoblasts. We aim to measure value of serum follistatin like 3 levels in the diagnosis of tubal ectopic pregnancy.
METHODS: 76 pregnant women including: 39 women with surgically confirmed tubal ectopic pregnancy and 37 healthy, singleton controls whose gestational ages were between 5 to 8 weeks. Serum FSTL3 levels were measured in both groups via ELISA. ROC curve analysis was performed for the prediction of tubal ectopic pregnancy by using serum FSTL3.
RESULTS: Serum FSTL3 levels were significantly lower in the ectopic pregnancy group then controls (p <0.001). ROC analysis showed the area under the curve in the curve (AUC) was 0.811 (0.713-0.909; 95% confidence interval (CI)). The highest value of the sum of sensitivity and specificity in the ROC curve is the point where the FSTL3 level was 2160.7535 (cut-off value) with a sensitivity and specificity of 75.7% and 79.5%, respectively. Furthermore, in the subset analysis of patients with prior ectopic pregnancy showed serum FSTL3 was the highest in patients without any previous ectopic pregnancy (p<0.001).
DISCUSSION AND CONCLUSION: Low levels of serum FSTL3 may be a potential biomarker in the early diagnosis of tubal ectopic pregnancy.