The term “great obstetrical syndromes” was originally applied to pregnancy-related disorders such as preterm labor, preterm premature rupture of membranes, preeclampsia, spontaneous pregnancy loss, stillbirth, and abnormally delayed or accelerated fetal growth. All of them share a placental component as part of their etiology. 1 The underlying concept is one of multiple underlying etiologies that adversely interact with the maternal–fetal unit to initiate subclinical pathology that progresses to clinical manifestation that also results in fetal adverse outcome. This concept is applicable to conditions such as gestational diabetes mellitus (GDM): a metabolic disease where the combination of maternal predisposition and placental factors results in progressively impaired glucose tolerance with secondary maternal and fetal effects that typically manifest in the third trimester. 2 4 Understanding the contributory role of these interactions is important for prediction, screening, diagnosis, prognosis, and ultimately therapeutic interventions.