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

ObjectiveTo measure activin A concentrations in uterine washing fluid collected from women with couple infertility undergoing intrauterine insemination (IUI).DesignRetrospective case-control study.SettingTertiary 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.