# Related differences in fecal bacteria of Chinese northern pregnant women of different ages: associations with maternal clinical indicators and neonatal outcomes

## TL;DR

This study compares gut bacteria in pregnant women of different ages in northern China and links differences to maternal health and baby outcomes.

## Contribution

It identifies age-related changes in gut microbiota and their associations with maternal metabolism and neonatal outcomes in northern Chinese pregnant women.

## Key findings

- AMA women had higher AKP, 25(OH)D, and creatinine levels, while YMA women had higher Cu but lower Fe concentrations.
- YMA women had more stable gut bacteria with beneficial species like Bifidobacterium and fewer pathogens like Streptococcus.
- AMA women showed a 'high-complexity, low-efficiency' gut bacterial network, potentially leading to adverse pregnancy outcomes.

## Abstract

The gut microbiota, a vital “microbial organ,” influences digestion, immunity, and metabolism. Aging alters gut microbiota of pregnant women through metabolic and hormonal pathways, thereby impacting neonatal health. In this study conducted in northern China, we compared two groups: advanced maternal age (AMA, ≥35 years) and younger maternal age (YMA, 20–34 years), analyzing fecal bacteria and maternal metabolism via biomarker measurements and microbial sequencing. Results showed AMA had significantly higher serum levels of alkaline phosphatase (AKP), 25-hydroxyvitamin D [25(OH)D], and creatinine, while YMA exhibited higher Cu but lower Fe concentrations. Although the fecal bacteria of AMA participants showed greater diversity, the YMA group displayed a more stable bacterial composition, characterized by a higher abundance of beneficial bacteria (e.g., Bifidobacterium) and a lower prevalence of potential pathogens (e.g., Streptococcus). Metabolically, the fecal bacterial network in YMA participants was more integrated, whereas the AMA group showed a “high-complexity, low-efficiency” pattern with disrupted metabolic pathways, which may contribute to adverse pregnancy outcomes. This study highlights age-related dysbiosis of the fecal bacteria in pregnant women and its impact on maternal and neonatal health, advocating for personalized prenatal care strategies for women with AMA.