Temporal Dynamics of Gastrointestinal Microbiota during Pregnancy

Abstract

Background: Research about the gastrointestinal (GI) microbiota has demonstrated that it plays a crucial role in maintaining human physiologic homeostasis. In particular, it regulates inflammatory pathways, glucose and energy metabolism, and vitamin production that have significant relevance during pregnancy. Purpose: To characterize the structure of GI microbiota during pregnancy and changes that occur over time. Methods: This study expanded the scope of a large prospective longitudinal study looking at the influence of diet on vaginal microbiota during pregnancy and preterm birth (Birth, Eating and the Microbiota - BEAM, R01-NR014826). A subset of 20 women from the parent study was included in the sample and stool was collected monthly from 20 weeks gestation to birth. The specimens were analyzed using culture-independent molecular sequencing-based techniques following 16SrRNA gene polymerase chain reaction amplification. Descriptive analytics and advanced statistical modeling techniques were used to characterize the structure and the temporal dynamics of the GI microbiota during pregnancy. Results: Three enterotypes were identified at all taxonomic ranks. Members of Firmicutes were dominant at all levels. Enterotypes changed at each time point within subjects, forming 17 temporal enterotype profiles that classified into three enterotypes categories. Significant associations were identified between race, body mass index, fiber, iron, fat, protein, carbohydrate and sweets in the diet and specific GI microbiota. The associations were more pronounced at lower taxonomic ranks. Discussion: The findings of the study are important because they identify specific relationships between the microbial composition of the GI microbiota and factors such as body mass index and diet quality that are known factors implicated in adverse pregnancy outcomes. More research using a larger sample size is needed to verify these findings.