Pregnant women's oral microbiome and low-birth weight infant

Abstract

Objectives: The objective of the study was to identify the underlying oral microbiota factors among pregnant women that were associated with the delivery of low birth weight (LBW) baby by DNA sequencing technology. Methods: Thirty mothers who delivered an infant weighing < 2500g and 30 pregnant women who delivered healthy infant were investigated in this retrospective case-control study. The confounding variables of age, hypertension, and tobacco/alcohol usage were matched between two groups. Unstimulated saliva was collected from participants at their 12-20 gestational week. The total microbial genomic DNA was extracted. Microbial diversity and composition were characterized by sequencing the 16S rRNA gene amplicons. Results: The average birthweight (±SD) of the infants in LBW group was 2203 ± 293g, whereas in control group was 2963 ± 298g. There was no significant difference between the two groups in the prevalence and severity of periodontal diseases (p>0.05). The mothers who delivered LBW babies had higher species richness of salivary microbiota than the control group (measured by Chao1 and Abundance-based Coverage Estimator, p<0.05), whereas there was no significant difference in the Shannon and Simpson diversity indices (p>0.05) which indicated the different pathogens in the case group were in relatively small quantity. The Liner discriminant analysis Effect Size (LEfSe) was used to detect the differences in the microbiome between groups. At the genus level, LBW group had higher abundance of the obligate anaerobe Oribacterium (LDA score=2.85) compared with the control. At the species level, Streptococcus infantis was more abundant in case group (LDA score=3.70), as well as the gram-negative bacteria Prevotella nigrescens (LDA score=2.18), which has been proved to trigger an over-aggressive response from the immune system. Conclusions: A higher abundance of some periodontal disease-associated microbiota found in the saliva of pregnant woman is associated with the delivery of LBW babies.