Low expression of progesterone receptor A in intermediate trophoblast of miscarriages.

Objective: To examine the potential differences in the expression of Progesterone Receptor A and Estrogen Receptor A in intermediate trophoblastic cells at the implantation site in elective abortions and miscarriages by immunohistochemistry. Study Design: Twenty two (22) samples of miscarriages and eighteen (18) samples of elective abortions were obtained during gestational weeks 6 to 12. Monoclonal antibodies against Cytokeratin 7 and prolactin were used to help discriminate between trophoblastic and decidual cells at the feto-maternal interface on formalin-fixed paraffin-embedded sections. Samples were then stained with ERA and PRA antibodies. Nuclear expression was considered positive. Staining intensity was measured according to a 4 grade scale. Statistical analysis of the results was performed using the Mann-Whitney test and the Wilcoxon signed rank test. Results: PRA expression in intermediate trophoblastic cells was significantly higher in elective abortions (control group) compared to miscarriages. ERA expression was uniformly negative in both groups. Conclusion: PRA expression is significantly lower in intermediate trophoblastic cells of miscarriages compared to elective abortion pregnancies. Although this could be solely a result of a secondary event, it is still an important finding in the effort to unravel the complex molecular pathobiology of spontaneous abortions.