Pathology of the Stillborn Infant for the General Pathologist

Abstract

As the information obtained from previable fetal and stillbirth autopsies is used not only to explain the loss to the parents, but for future pregnancy planning, general pathologists need to be comfortable in dealing with these autopsies. The importance of an adequate fetal examination has been emphasized in a recent policy on the subject by the American Board of Pathology http://www.abpath.org/FetalAutopsyPoli'cy.pdf. This second review paper covers the approach to hydrops fetalis. The approach to the nonanomalous and anomalous fetus was covered in the first part of this series.

Nonimmune hydrops foetalis: value of perinatal autopsy and placental examination in determining aetiology

“…Mechanical obstruction of great vessels due to enlarged urinary bladder with resultant reduced venous return to heart is the underlying pathology. 12 Early onset oligohydramnios secondary to BOO leads to pulmonary hypoplasia, further reducing the survival chances.…”

A Pathologist’s Approach to Nonimmune Hydrops

“…Two large recent studies each, found that a little more than 20 % of the cases were due to cardiovascular causes [11,17,18]. These cardiovascular etiologies may derive either from an intrinsic cardiac abnormality or from an external anomaly that leads to high output cardiac failure [5,6]. Relevant external anomalies include vascular malformations or large, vascular tumors [5,8].…”

“…These cardiovascular etiologies may derive either from an intrinsic cardiac abnormality or from an external anomaly that leads to high output cardiac failure [5,6]. Relevant external anomalies include vascular malformations or large, vascular tumors [5,8]. A considerable number of structural cardiac anomalies have been associated with NIH [19].…”

“…A considerable number of structural cardiac anomalies have been associated with NIH [19]. Among these, the more common include atrioventricular canal defect, left heart hypoplasia, right heart hypoplasia, tetralogy of Fallot, in utero closure of the foramen ovale or ductus arteriosus, and Ebstein anomaly [5,6,8,11]. Rhythm disturbances are another frequent cardiac cause of NIH.…”

“…Polyhydramnios and a thickened placenta (on ultrasound examination) often accompany the fluid accumulations in body compartments but are not typically considered as diagnostic criteria [3,4]. Due to a number of physiologic differences between intrauterine and extrauterine life, fluid accumulation in fetal tissues occurs more easily than in an infant or adult, and this process readily extends to the generalized edema with fluid collections in body cavities characteristic of hydrops [5]. The pathophysiologic processes underlying interstitial fluid accumulation in hydrops include (but are not limited to) cardiac dysfunction (particularly those disorders that result in increased central venous pressure), anemia (generally with high output cardiac failure), lymphatic obstruction, altered endothelial cell integrity with increased capillary permeability and hypoproteinemia (as seen with disruptions to hepatic synthetic capacity) [5,6].…”