The present invention aims to prevent and/or treat health-related conditions in infants born with a non-optimal intestinal microbiome, by providing specific probiotic lactic acid bacterial strains to the pregnant mother. This will enable early colonization of the infant gut, even before birth, and thus prevent and/or treat health-related conditions associated with non-optimal microbiome. Thus, the present invention provides a probiotic microorganism for use in the treatment of a fetus or neonate, wherein said probiotic microorganism is administered to the oral cavity of a pregnant female in a formulation suitable to colonize the oral cavity, wherein said probiotic microorganism is thereby administered to the fetus. The methods and uses of the invention can also provide for the colonization of a fetus or neonate or for shifting the microbiome of a fetus or neonate
