Evaluation of endometrial activin A secretion for prediction of pregnancy after intrauterine insemination

OBJECTIVE: To measure activin A concentrations in uterine washing fluid collected from women with couple infertility undergoing intrauterine insemination (IUI). DESIGN: Retrospective case-control study. SETTING: Tertiary university center for women's care. PATIENT(S): Fifty women, of whom 25 became pregnant after up to three IUI attempts and 25 did not. INTERVENTION(S): Endocrine and clinical evaluation, semen analyses and hypo-osmotic swelling test, ovarian stimulation, endometrial thickness measurement by ultrasound, uterine washing fluid collection by sonohysterography, and IUI. MAIN OUTCOME MEASURE(S): Activin A measurement by enzyme-linked immunosorbent assay, receiver operating characteristics curve analysis, and pregnancy rates after IUI; sensitivity, specificity, positive and negative likelihood ratios of activin A, and endometrial thickness for pregnancy prediction. RESULT(S): Activin A was measurable in all samples evaluated, and the levels (mean +/- SEM) were statistically significantly higher in the pregnant (0.08 +/- 0.01 ng/mL) than in the nonpregnant (0.022 +/- 0.001 ng/mL) group. Activin A at the cut off of 0.04 ng/mL achieved a sensitivity of 76.0 % (95% CI, 54.9%-90.6%) and a specificity of 100% (95% CI, 86.2%-100%) as a single marker for prediction of pregnancy. CONCLUSION(S): Activin A is secreted into uterine lumen; the levels in endometrial washing fluids were higher in women who subsequently became pregnant after IUI, so its measurement may be useful in predicting successful implantation