Table 2.

Overview of microchimerism in maternal health and disease

Tissue	Disease/Function	Sample	Species	Fetal cell association with maternal health or disease	Findings
Brain	Alzheimer's disease	Brain	Human	Health	Fetal cells found less frequently in tissue of patients compared to healthy controls 75
	Parkinson's disease	Brain	Mouse	Disease	Fetal cells found more frequently in disease tissue compared to healthy controls initially, but not after long‐term observation 47
Breast	Cancer	Blood/Breast	Human	Health	Fetal cells less frequent in blood and tissue of patients compared to healthy controls 54, 55, 56, 57
	Cancer	Breast	Human	Health	Lower levels of fetal cells in ER/PR‐positive breast cancer tissue compared to healthy controls 53
	Cancer	Breast	Human	Disease	Higher levels of fetal cells in HER‐2 breast cancer tissue compared to healthy controls 53
	Cancer	Breast	Human	Disease	Presence of fetal‐derived cells in tumor stroma 58
	Cancer	Breast	Mouse	Disease	Fetal cells are present in murine breast carcinomas. High‐grade tumors contain more fetal cells 59
Thyroid	Cancer	Blood/Thyroid	Human	Health	Fetal cells/male DNA found more frequently in the blood of healthy controls compared to patients. Found no significant difference in tissue samples 66
	Cancer	Thyroid	Human	Disease	Fetal cells found more frequently in the disease tissue of patients compared to healthy tissue 44, 66
	Hashimoto's thyroiditis	Blood/Thyroid	Human	Disease	Fetal cells/male DNA found more frequently in patients compared to healthy controls 44, 68, 69, 70, 113
	Graves' disease	Blood/Thyroid	Human	Disease	Fetal cells/male DNA found more frequently in patients compared to healthy controls 69, 70, 71
	Thyroiditis	Thyroid	Mouse	Disease	Fetal cells found more frequently in patients compared to healthy controls 67
Immune system	Systemic sclerosis	Blood/Skin lesion	Human	Disease	Fetal cells/male DNA found more frequently in patients than healthy controls 49, 79, 80
	Systemic sclerosis	Blood	Human	No association	No difference in frequency of male DNA between patients and controls 87, 88
	Sjögren syndrome	Blood/Salivary gland	Human	Disease	Male DNA was higher in tissue but not in blood in patients compared to healthy controls 81
	SLE	Blood	Human	Disease	Male DNA/fetal cells higher in patients than healthy controls 82, 83
	SLE	Multiple tissues	Human	Disease	Fetal cells/male DNA found more frequently in damaged tissue compared to healthy tissue 114
	SLE	Blood	Human	No association	No difference in frequency or quantity of male DNA between patients and controls 89
	Rheumatoid arthritis	Nodule	Human	Disease	Male DNA detected in rheumatoid nodules 86
	Rheumatoid arthritis	Blood	Human	Disease	Prevalence of fetal cells/male DNA higher in patients than healthy controls 83, 84
	Rheumatoid arthritis	Blood	Human	No association	No difference in male DNA between patients and controls 90
Lungs	Cancer	Lung/Thymus	Human	Disease	Fetal cells found more frequent in diseased tissue compared to healthy tissue from same patient 92
Heart	Injury model	Heart	Mouse	Health	Fetal cells home to injured maternal hearts and differentiate into endothelial cells, smooth muscle cells, and cardiomyocytes 48
	Cardiomyopathy	Heart	Human	Disease	Fetal cells were found in found in patients, but not healthy controls 10
Liver/Kidney/Spleen	Injury model	Injured tissue	Mouse	Health	Fetal cells home to injured tissues 41, 42
Reproductive tissues	Cancer	Cervical tissue	Human	Disease	Male fetal cells found more frequently in tissue of patients compared to controls 115
	Cancer	Endometrial tissues	Human	No association	Male DNA found in both benign and diseased tissue 116
	Endometriosis	Endometrial tissues	Human	No association	Male DNA were not observed in disease or healthy tissue 117
Colon	Cancer	Blood	Human	Disease	Fetal cells found more frequently in the blood of patients compared to healthy controls 56
Skin	Caesarean section	Skin	Human	Health	Fetal cells identified in some healed maternal CS scars and expressed cytokeratin, and collagen I, III, and TGF‐β3 in healed maternal scar 16
	Injury model	Skin	Mouse	Health	Fetal cells more frequent in maternal inflamed tissues and participate in maternal angiogenesis and inflammation 17, 40
	Melanoma	Skin	Human/Mouse	Disease	Fetal cells detected more frequently in melanoma compared to benign or healthy tissue 118
	PEP	Skin	Human	Disease	Male DNA detected in tissue of patients with no detection in healthy controls 85

SLE, systemic lupus erythematosus; PEP, polymorphic eruptions of pregnancy; CS, cesarean section.

A summary of the current literature on fetal cell microchimerism and the proposed association with maternal health and disease.