In 2015, approximately 2.6 million fetal deaths (greater than 28 gestational weeks) occurred worldwide. The ACOG (American College of Obstetricians and Gynecologists) Committee on Genetics has recommended that placental examination should become a routine clinical tool in stillbirth evaluation. The placenta undergoes profound developmental changes during its lifespan. For example, the villous tree undergoes changes in morphology and components, which are collectively referred to as villous maturation. Defective villous tree maturation can cause diminution of vasculosyncytial membranes, resulting in placental dysfunction and fetal hypoxia. Yet, there were no studies that have evaluated disorders of villous maturation in placentas of structurally normal stillbirths.
PRB researchers ascertained the frequency of disorders of villous maturation, as well as other placental histopathologic lesions in fetal deaths occurring over a 12 year period. The study population consisted of 944 controls and 143 fetal deaths. The most prevalent placental histopathologic lesions in structurally normal stillbirths as compared to controls included disorders of villous maturation, histologic patterns suggestive of hypoxia, fetal vascular malperfusion, maternal vascular malperfusion, and chronic placental inflammation. Specifically, the placentas of women with fetal death were 44 times more likely to present disorders of villous maturation, compared to placentas of controls. This suggests that the burden of placental disorders of villous maturation lesions is substantial.