STC1 and kidney failure: One possible role for STC‐1 is inhibiting the activity of pregnancy‐associated plasma protein‐A (PAPP‐A), a proteolytic enzyme that cleaves the inhibitory binding protein IGFBP4 and prevents the release of active IGF‐1.9 Circulating maternal IGF‐1 acts to both reduce blood pressure and stimulate fetal growth.10 It has also been proposed that the effects of STC‐1 on the kidney could account for the proteinuria and renal failure that can accompany preeclampsia.8, 11