Unique observations about the endometrial microbiome during early pregnancy in a case of successful gestation and spontaneous abortion

Here we describe for the first time as an incidental finding, the human endometrial microbiota present in a successful 4th week pregnancy and in a previous 8th week spontaneous clinical miscarriage in the same patient with euploid embryos, in both cases. We demonstrate less bacterial diversity and higher Lactobacillus abundance during healthy pregnancy compared to spontaneous abortion. These novel observations might have profound implications for the understanding of the microbiology of healthy and pathological human pregnancy and its clinical translation.