Purpose: Retrospective cohort studies have shown a relationship between maternal serum interleukin-1β (IL-1β) and interleukin-1 receptor antagonist (IL-1Ra) levels and in vitro fertilization (IVF) cycle outcome. The objective of this investigation was to explore the correlation between serum IL-1β and/or IL-1Ra levels obtained prospectively and IVF outcomes.
Methods: Sera from 205 women were collected just prior to initiation of their IVF cycle, at the time of human chorionic gonadotropin administration, day 24 of IVF cycle, day 28, and day 35. Sera were analyzed for IL-1β and IL-1Ra using commercially available ELISA kits. Cycle outcomes were followed prospectively. Data were analyzed using Friedman analysis of variance by ranks and chi-square analysis.
Results: Among women with a viable pregnancy, IL-1β serum levels increased over time for those that proceeded to deliver or had an ongoing pregnancy. There was no increase in serum levels for those with subsequent pregnancy loss. Of the women that had an embryo transfer, detectable IL-1β levels at the start of the cycle were associated with successful IVF outcome (p = 0.027). Of women with a positive pregnancy test, undetectable IL-1β at the start of the cycle were associated with subsequent pregnancy loss (p = 0.046). For all IL1-Ra serum analysis, there were no significant results.
Conclusions: The increasing levels of IL-1β over time are consistent with the known role of the IL-1 cytokine family in implantation and pregnancy. Additionally, we confirm in a prospective investigation the positive relationship between detectable serum IL-1β at the start of IVF cycle and outcome.
Keywords: IVF; Interleukin-1; Live birth; Serum cytokine.