PREIMPLANTATION FACTOR (PIF) PREDICTS SUBSEQUENT PREGNANCY LOSS

PROBLEM: To evaluate the ability of preimplantation factor (PIF) measu red in the lymphocyte/platelet binding assay (LPBA) to predict subsequ ent spontaneous abortion. METHOD: Serum from 57 women experiencing fir st trimester pregnancy losses were stud led using the LPBA (46 women c onceived after in vitro fertilization and embryo transfer for treatmen t of infertility and 11 with a history of unexplained recurrent sponta neous abortion conceived spontaneously). The assay employs a combinati on of heat inactivated sera with donor O+ lymphocytes and platelets, c omplement and an antibody against CD2, Chromosome analysis was perform ed on 32 of the abortuses. Results of PIF assay were compared between karyotypically normal and abnormal abortuses. RESULTS: PIF assay was n egative in all 57 women at the time of abortion. Among 12 karyotypical ly normal abortuses only 1 woman (8%) had an initial positive PIF 11 ( 92%) had negative PIF. Serial PIF assays were performed on 15 women. P IF assay became negative a minimum of two weeks prior to demonstration of intrauterine demise at a time when hCG concentrations remained ele vated. A trend to subnormal was seen in women with normal when compare d to those with abnormal abortus karyotype, but the numbers were too s mall to reach statistical significance (P = 0.09). CONCLUSION: Measure ment of PIF throughout the first trimester of pregnancy predicts subse quent pregnancy loss.