Practicing perinatal pathologists and placental pathologists were invited (by authors T.Y.K., E.E.M., and S.J.G.) to participate in a 1-day workshop to derive recommended standards for placental examination and sampling, and consensus agreement for diagnostic criteria for placental lesions. Research-active placental pathologists and maternal-fetal medicine specialists with a strong placental research interest were identified by a search of authors through PubMed and by reputation, while an open invitation was also issued through a global pediatric pathology e-Web to all practicing perinatal pathologists. The group comprised 52 people who were contacted directly; 40 people expressed an interest in attending, of whom 27 (68%) actively participated before the meeting by prioritizing placental pathology lesions for discussion and potential areas of controversy or uncertainty and opinions, which were then circulated prior to the workshop. The group also built on a well-constructed series of definitions of three placental patterns of disease (fetal vascular obstruction, maternal vascular underperfusion [then termed], and inflammatory conditions).5–7 Twenty-six pathologists were able to attend and participate in the workshop held in Amsterdam, the Netherlands, in September 2014. Following discussion and presentation of evidence, where available, the group constructed recommendations to standardize definitions of lesions.