Serum activin A levels are lower in tubal than intrauterine spontaneously conceived pregnancies

Objective. To measure serum activin A levels together with progesterone and hCG, in women with overt clinical signs and symptoms of ectopic pregnancy (EP) and, in gestational age-matched intrauterine pregnancy (IUP). Design. Retrospective case-control study. Setting. Department of Pediatrics, Obstetrics and Reproductive Medicine, Section of Obstetrics and Gynecology, University of Siena, Siena, Italy. Population. The study group was composed by 30 women with an EP; the control group was composed by 30 women with a sonographic evidence of a single spontaneous IUP. Methods. Clinical examination; transvaginal ultrasound scan; hCG, progesterone and activin-A measurements; laparoscopy; uterine curettage; histological examination. Main Outcome Measure. Pregnancy outcome; sensitivity and specificity of hCG, progesterone, and activin A for EP. Results. Serum hCG levels did not differ significantly between tubal EP and IUP, while P concentrations were significantly (P < 0.001) lower in tubal EP than IUP. Serum levels of activin A were significantly (P < 0.0001) lower in tubal EP than in IUP and, at the cutoff 0.43 ng/mL achieved a sensitivity of 96.7% and a specificity of 100% for EP. Conclusion. Activin A secretion in EP is reduced and measurement of its serume levels may have the potential clinical advantage to signal the presence of EP.