Stillbirth, defined in the U.S. as fetal death after 20 weeks 0/7 days or weight greater than 350 grams (if gestational age is unknown), is one of the most common adverse pregnancy outcomes, affecting over two million pregnancies worldwide annually.1 Approximately 21,000 stillbirths occur in the United States per year, with majority occurring in low- and middle-income countries. Stillbirth continues to be a major public health concern, as fetal deaths have remained virtually unchanged since 2019.2 In the Stillbirth Collaborative Research Network (SCRN) study approximately one quarter of stillbirths remained unexplained despite complete evaluation, while the remaining were categorized into the following causes: obstetrical complications (29%), placental abnormalities (24%), fetal malformations (14%), infections (13%), umbilical cord abnormalities (10%), hypertensive disorders (9%), or other medical complications of pregnancy (8%).3

Placental abnormalities such as placental abruption, chorioangioma, vasa previa, velamentous cord insertion, or umbilical cord thrombosis have been associated with an increased risk of stillbirth.4,5 While placental abnormalities may be the only abnormality noted in about one-quarter of stillbirth causes, gross and histologic changes of the placenta can be seen when stillbirth is associated with other etiologies. Thus, placental evaluation is considered to be one of the most useful tools for the evaluation of stillbirth.5 The American College of Obstetrics and Gynecology recommends gross and histologic examination of the placenta, umbilical cord, and fetal membranes by a pathologist familiar with placental pathology as a vital component of stillbirth evaluation.4,5 The Amsterdam Placental Workshop Group consensus was published in 2016 as an effort to create a standard protocol for sampling the placenta along with diagnostic criteria for placental lesions.6 Here we discuss placental and umbilical cord abnormalities, gross and histologic changes in the placenta associated with stillbirth, as well as possible future ultrasound innovations for assessing stillbirth.