This paper notes the previously known histological (looking down the microscope) similarity between placental malaria and CHI and suggests that they may both result/be due to cells ‘expressing’ receptors on their surface. They looked at cells from CHI placentas as well as cells from normal placentas and those from CVUE placentas and found that there were indeed an increase in some specific ‘Toll-like receptors (TLR). They noted that there was a difference in which receptors were seen but suggest that this could still suggest that CHI could be an immune system related phenomenon. They suggest that this could be due to the mother having a blood-borne bacterial infection that her body could be fighting off (even if she isn’t outwardly unwell).
They are aware that multiple pregnancies could be affected by CHI and thus this infection would have to either recur or be continuing to happen over multiple pregnancies. They say that CHI over more than one pregnancy has not been officially found, I’m not sure if this is still/actually the case.