The aims of this study are threefold: (a) to determine the cellular origin of STC‐1 in the placenta, (b) to investigate how the secretion of STC‐1 is regulated, and (c) to determine whether first trimester placental tissue from the pregnancies at increased risk of developing preeclampsia secrete more STC‐1 than tissue from low‐risk pregnancies. This evidence concerns the gene STC1 and preeclampsia.