Trophoblast inclusions in the human placenta: Identification, characterization, quantification, and interrelations of subtypes

We sought to examine placentas enriched for trophoblast inclusions (TIs) in order to characterize, quantify, and examine the interrelations between subtypes of TIs to better understand their underlying biology. We examined a cohort of 600 placentas from deliveries between 20(0) and 43(0) weeks of gestation. Forty-five percent of the placentas had at least one TI in the two slides examined. Four percent of the placentas had 10 or more TIs and two placentas had more than 70 TIs. Four distinct TI subtypes were observed: inclusionoids (early forming inclusions), inclusions, calcified inclusions, and calcified bodies. We suggest this reflects a developmental trajectory of TI maturation, the timing of which might be useful when comparing TI expression to clinical outcomes.

Automated summary

The study identified four different subtypes of trophoblast inclusions (TIs) in placentas, including inclusionoids, inclusions, calcified inclusions, and calcified bodies. The number of TIs present and the timing of their expression in placentas may be related to clinical outcomes.