Table 1.

Mechanisms of cross‐talk between maternal microbiota and offspring immunity

Study theme	Outcome	Species	Refs
Maternal microbiota influence fetal microbiota	1.Maternal gut bacteria translocate to meconium in offspring	Mouse	73
	2.Fetal gut is colonized with bacteria during pregnancy	Human	76, 77, 78
	3.Placenta harbors a unique microbiome	Human	5, 9
Maternal microbiota influence infant microbiota and immunity	1.Maternal gut strains are more persistent in infant gut compared to those from vagina and skin	Human;	11
	2.Maternal microbiota during gestation impacts offspring microbiota and immunity	Mouse	1, 12, 20
	3.Offspring born to mothers with an altered microbiota are susceptible to viral and bacterial infections	Mouse	99, 100
	4.Maternal gut microbiota indirectly impacts extraintestinal microbiota	Mouse	1
Bacterial metabolites	1.SCFA impact intestinal immunity	Mouse;	86, 87, 89, 90, 101
	2.SCFA produced during pregnancy impact fetal immunity	Mouse	12, 91, 93
Maternal IgG	1.Maternal gut microbiota during pregnancy impacts maternal IgG effectively influencing passive immunity to offspring	Mouse	1
	2.Immunoglobulins are involved in microbial opsonization	Human;	97
	3.IgG mediates bacterial transfer in utero	Mouse	12