Kreines FM, et al. – Researchers investigated the relationship between serum interleukin-1β (IL-1β) and/or interleukin-1 receptor antagonist (IL-1Ra) levels obtained prospectively and in vitro fertilization (IVF) outcomes. For IL-1β and IL-1Ra, researchers analyzed sera from 205 women 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. They followed cycle outcomes prospectively. Researchers observed consistent increasing levels of IL-1β over time with the known role of the IL-1 cytokine family in implantation and pregnancy. Furthermore, they identified a positive relationship between detectable serum IL-1β at the start of IVF cycle and outcome.