An evaluation of peripheral blood platelet enumeration as a monitor of fertilization and early pregnancy.

This paper reports our data that confirm the existence of early pregnancy-associated thrombocytopenia (EPAT) in the mouse and illustrate that the phenomenon is independent of age, parity, and strain differences. This paper also provides evidence that the EPAT phenomenon is induced by a soluble factor (EPAT-factor) released by the fertilized ovum. EPAT-factor was produced in vitro by mouse embryos from the 1-cell stage to the expanded blastocyst stage. The human study involved a "blind" analysis of serum samples, collected from in vitro fertilization-treated patients, for the presence of thrombocytopenic activity. Results suggest that measurement of this thrombocytopenic activity might be useful as an index of embryo viability and might be clinically applicable for the monitoring of implantation success in in vitro fertilization programs.