Placental surface shape, function, and effects of maternal and fetal vascular pathology

Abstract

Goal In clinical practice, variability of placental surface shape is common. We measure the average placental shape in a birth cohort and the effect deviations from the average have on placental functional efficiency. We test whether altered placental shape improves the specificity of histopathology diagnoses of maternal uteroplacental and feto-placental vascular pathology for clinical outcomes. Materials and Methods 1225 placentas from a prospective cohort had chorionic plate digital photographs with perimeters marked at 1–2 cm intervals. After exclusions of preterm (n=202) and velamentous cord insertion (n=44), 979 (95.7%) placentas were analyzed. Median shape and mean perimeter were estimated. The relationship of fetal and placental weight was used as an index of placental efficiency termed “β”. The principal placental histopathology diagnoses of maternal uteroplacental and fetoplacental vascular pathologies were coded by review of individual lesion scores. Acute fetal inflammation was scored as a“negative control” pathology not expected to affect shape. ANOVA with Bonferroni tests for subgroup comparisons were used. Results The mean placental chorionic shape at term was round with a radius estimated at 9.1 cm. Increased variability of the placental shape was associated with lower placental functional efficiency. After stratifying on placental shape, the presence of either maternal uteroplacental or fetoplacental vascular pathology was significantly associated with lower placental efficiency only when shape was abnormal. Conclusions Quantifying abnormality of placental shape is a meaningful clinical tool. Abnormal shapes are associated with reduced placental efficiency. We hypothesize that such shapes reflect deformations of placental vascular architecture, and that an abnormal placental shape serves as a marker of maternal uteroplacental and/or fetoplacental vascular pathology of sufficiently long standing to impact placental (and by extension, potentially fetal) development.

Maternal Demographic and Placental Risk Factors in Term Low Birth Weight in Ghana

“…Thus, a greater shift leads to a lower level of vascular distribution available for nutrient exchange (and vice versa) [24]. The largest distance from the point of centrality is a high risk factor to term LBW in our population.…”

“…Interestingly, there was little evidence in our study that vascular tree structure associated with LBW suggesting that the structure may not strongly impact the volume or available surface area for nutrient exchange in the study population. The vascular tree has been suggested to be the sole source of oxygen and nutrient to the fetus, thereby defining placental efficiency [23,24]. Thus, it appears that nutrient delivery to the fetus may be minimally affected if placental efficiency in nutrient delivery is not unduly compromised by the vascular tree morphology.…”

“…Placental factors include changes in placental morphology and insults to the placenta such as infarcts, chronic villous inflammation, and vascular vessel thrombosis. Placental morphological changes include the length, breadth, weight and any shifts from central insertion of the umbilical cord on the chorionic plate to an irregular velamentous insertion [23,24]. Such changes affect the placental efficiency with regards to adequate development of the vasculature to meet the nutrient and oxygen supply to the fetus [25,26].…”

Regions of variable DNA methylation in human placenta associated with newborn neurobehavior

“…2,3 The placenta expresses a number of neuropeptide and endocrine hormones, 4 and alterations to placental physiology have been associated with a number of acute and long-term outcomes in the developing infant. 5,6 Epigenetic regulation of the placental genome can influence placental function and signaling, with long-term impacts on fetal health. This study focuses on DNA methylation, a chemical modification that typically occurs in cytosines that are followed by guanine (known as CpGs).…”

Characterizing Placental Surface Shape with a High-Dimensional Shape Descriptor

“…Using a Tablet PC and GNU Image Manipulation Program (GIMP), the perimeter was traced in green, the umbilical cord insertion marked in yellow and the blood vessels traced in pink. While automatic vessel extraction and perimeter detectors are being developed by, e.g., [4], they are still far from perfect for this data set. Therefore, we select the 150 hand-traced images to be the ground truth for the perimeter shape and the vascular structure.…”