Good fertilization results associated with high IL-1beta concentrations in follicular fluid of IVF patients

To determine the levels of interleukin-1 beta (IL-1beta) in follicular fluid and embryo culture fluid after controlled ovarian hyperstimulation and to assess the association of this cytokine with the outcome of in vitro fertilization (IVF) or intracytoplasmic sperm injection (ICSI) treatment and embryo transfer.

A total of 256 couples undergoing the IVF/ICSI program were included in this prospective study. Zygote quality, embryo and blastocyst morphology were evaluated, and embryo transfer was performed 5 days after oocyte recovery. IL-1beta concentrations were measured in follicular fluid and embryo culture fluid of the third and fifth culture days.

Embryo replacement was performed with a median of 2 embryos per cycle. In all, 44 clinical pregnancies were achieved in 256 assisted reproductive technology (ART) cycles (pregnancy rate: 19.8% per transfer). Follicular fluid concentrations of IL-1P were not significantly different in pregnant (2.1 pg/mL) and nonpregnant women (2.7 pg/mL). Follicular fluid of lVF, but not ICSI, patients with good fertilization rates (> 90%) contained significantly higher levels of IL-1beta (3.3 pg/ mL) than did follicular fluid of women with fertilization rates < or = 90% (2.0 pg/mL, p < 0.05). No correlation was found between intrafollicular IL-1beta and zygote morphology, day 3 and day 5 embryo morphology. There was no relationship between IL-1beta in culture fluid supernatants and embryonic development.

In IVF patients high levels of intrafollicular IL-1beta were associated with good fertilization rates. There seems to be no correlation between IL-1beta concentrations in follicular fluid or embryo culture fluid and embryo morphology or pregnancy outcome of ART cycles.