Activin A and Follistatin as Biomarkers for Ectopic Pregnancy and Missed Abortion

Abstract EN

Activin A as a predictor of pregnancy failure has been the focus of heated debate, but the value of a combined activin A and follistatin (FS) measurement in serum to predict pregnancy failure has not been reported yet.

We assessed whether a single serum measurement of the two physiological antagonists at 6–8 weeks gestation could differentiate ectopic pregnancies (EP) or missed abortions (MA) from healthy intrauterine pregnancies (IUP).

activin A concentrations were significantly lower in women with EP (n = 30, median value of 264 pg/mL) and women with MA (n = 30, median value of 350 pg/mL) compared to IUP (n = 33, median value of 788 pg/mL); P<0.001.

At a threshold value of 505 pg/mL, activin A had 87.9% sensitivity and 100% specificity and negative predictive value of 0.974 for discriminating an ectopic pregnancy from viable pregnancies.

FS was able to discriminate IUP from EP (ROC curve P<0.001) as was their ratio (ROC curve P=0.008), but was unable to discriminate a MA from an EP.

In EP, activin A did not correlate with beta HCG levels.

The present findings support the thesis that activin A or FS could be considered promising biomarkers for the discrimination between an IUP and a failed pregnancy (MA or EP).