Use of a bioassay for embryo-derived platelet-activating factor as a means of assessing quality and pregnancy potential of human embryos.

The production of an embryo-derived platelet-activating factor (PAF) was recently shown to have a correlation with embryo quality and viability. The detection of this factor was used as a means of examining the effect of various aspects of the in vitro fertilization and embryo transfer procedure on human preimplantation embryo quality. Embryos that resulted in pregnancy produced significantly higher levels of embryo-derived PAF in vitro than embryos that failed to result in pregnancy. Of a further 85 embryos, 43% had a level of embryo-derived PAF that fell in the same range as the embryos that resulted in pregnancy. The production of embryo-derived PAF was related to the type of treatment used to induce follicular development (with clomiphene citrate and human menopausal gonadotropin commencing on day 5 giving best results); the size and estradiol production of the follicles producing the embryo; the age of the embryo culture medium; and the morphology and cell number of the embryos.