The forgotten fragment: Unmasking a rare case of calcified retained placenta at 20 weeks postpartum

Introduction: Retained products of conception (RPOC) are a recognized cause of secondary postpartum hemorrhage, most commonly occurring within the early postpartum period. However, delayed presentations with calcified RPOC are rare and pose unique diagnostic challenges. While advanced maternal age, uterine atony, prior cesarean sections, and abnormal placentation— such as placenta accreta spectrum and succenturiate placenta—are common risk factors, RPOC can also occur in low-risk patients and require careful clinical management. Case Report: A 25-year-old G1P1 woman with an uncomplicated pregnancy and vaginal delivery presented with persistent intermittent bleeding 20 weeks postpartum. Despite undetectable serum hCG levels and no signs of infection, serial ultrasounds revealed a calcified mass at the uterine fundus. The patient underwent hysteroscopy with dilation and curettage (Dand C), confirming the presence of calcified placental fragments with fibrosis. Her symptoms resolved postoperatively, and no complications were observed. The findings suggest a likely retained succenturiate lobe, an uncommon placental abnormality that was undetected in the immediate postpartum period. Conclusion: This case highlights the importance of clinical vigilance and timely intervention in managing postpartum complications, particularly in an evolving obstetric population where advanced maternal age and the use of assisted reproductive technologies are becoming more prevalent. Early identification of RPOC, aided by imaging modalities such as ultrasound and saline infusion sonohysterography, and prompt treatment with hysteroscopy and Dand C are essential to prevent complications such as chronic endometritis and intrauterine adhesions. Recognizing rare placental anomalies is critical for optimizing patient outcomes.