Placental and cord insertion pathologies: screening, diagnosis, and management

Placenta previa, low-lying placenta, and placenta accreta are aberrations in the normal development of the placenta. Diagnosis in the prenatal period is essential because each of these pathologies can have a profound impact on the management of labor, birth, and the third stage. In recent years, there has been an increase in the occurrence of these placental abnormalities, with the increase in the cesarean rate considered to be a main cause of this phenomenon. Comprehensive risk assessment, combined with recent advances in ultrasonography, can provide earlier detection of impaired placental implantation. Umbilical cord insertion pathologies are also of concern. Velamentous cord insertion is a defect in the insertion site of the umbilical cord resulting from the atrophy of portions of the developing placenta. In this condition, the blood vessels of the umbilical cord are not protected by Wharton's jelly, resulting in a potential for increased risk of breakage when the amniotic membranes rupture. Vasa previa is a velamentous insertion of the umbilical cord in which the blood vessels are present over the cervical os. If these blood vessels rupture during labor, it can have catastrophic effects on the fetus. Prenatal diagnosis of this condition can allow the certified nurse-midwife/certified midwife (CNM/CM) to plan for the safe birth of the newborn and avoid fetal hemorrhage. This article provides a review of risk factors, diagnosis pathophysiology, and management options for these conditions, thus enabling the CNM/CM to provide safe, effective care and management.