Background: The aim of this extended review of multicenter case series is to describe the prenatal ultrasound features and pathogenetic mechanisms underlying placental and umbilical cord anomalies and their relationship with adverse perinatal outcome. From an educational point of view, the case series has been divided in three parts; Part 1 is dedicated to placental abnormalities. Methods: Multicenter case series of women undergoing routine and extended prenatal ultrasound and perinatal obstetric care. Results: Prenatal ultrasound findings, perinatal care, and pathology documentation in cases of placental pathology are presented. Conclusions: Our case series review and that of the medical literature confirms the ethiopathogenetic role and involvement of placenta abnormalities in a wide variety of obstetrics diseases that may jeopardize the fetal well-being. Some of these specific pathologies are strongly associated with a high risk of poor perinatal outcome.