Maternal serum interleukin-33 and soluble ST2 across early pregnancy, and their association with miscarriage.

A shift from type 1 to type 2 immune bias is essential for successful implantation and pregnancy. ST2 is a receptor present on type 2 immune cells and IL-33 was recently discovered to be its ligand. We measured serum levels of soluble ST2 (sST2) and IL-33 across the mid-first trimester and examined whether levels were dysregulated among women with a viable fetus but destined to miscarry. While there was no significant change in sST2 or IL-3 across the first trimester, we found that women with live pregnancies destined to fail had dysregulated levels of serum IL-33, and potentially sST2 at six weeks' gestation.