Significance: We provide evidence of a decidualization defect in the endometrium of women with severe preeclampsia (PE) that was detected at the time of delivery and persisted years after the affected pregnancy. We went on to link this defect to impaired cytotrophoblast invasion. The transcriptional signature of the defect could enable its detection before (or after) conception, which would aid the development of therapies focused on improving decidualization and perhaps preventing severe PE.