Tumor necrosis factor is present in maternal sera and embryo culture fluids during in vitro fertilization

Abstract

The incidence of tumor necrosis factor alpha (TNF) in sera of women undergoing in vitro fertilization (IVF) and in embryo culture fluids was evaluated using an enzyme-linked immunosorbant assay. Just prior to embryo transfer to the uterus, 24 of 49 maternal sera (49.0%) contained TNF. The incidence and range of TNF concentrations (84–920 pg/ml) did not differ between women with eventual successful pregnancies and women who subsequently suffered preclinical or clinical abortions. At 8 days post-embryo transfer, 24 of 56 sera (42.9%) contained TNF. Again, the occurrence of TNF was of no predictive value for the eventual outcome of the pregnancy. TNF was also detected in culture fluids from the in vitro fertilized eggs of 12 of 49 women (24.5%). In 9 women, TNF was detected in each of the embryo culture fluids tested. As was the case for sera, the presence or absence of TNF in the culture fluids was unrelated to pregnancy outcome. In 21 patients, paired sera and culture fluids were analyzed. In 9 of 10 women with TNF in their culture fluids, TNF was also present in the corresponding serum. Of 12 women with serum TNF, 9 also had TNF in their culture fluids. Since the culture fluids contained 10% maternal sera, it appeared that in most cases TNF in the culture fluids was derived, at least in part, from the serum. However, in 6 of 9 women TNF levels in the cultures exceeded levels in the corresponding sera. TNF was also identified in 2 of 10 culture fluids in which Plasmanate was substituted for serum. The embryo itself and/or associated granulosa cells may also contribute to TNF in the in vitro culture fluids. We conclude that TNF production is a normal consequence of the hyperstimulation of ovulation induction in women undergoing IVF and that TNF, at the levels detected, appears not to be detrimental to the viability or development of the pre-implantation stage embryo.