Preterm birth alters the gut microbiota, metabolome and health outcomes of twins at 12 months of age.

Ten group-specific gut microbiota genera were identified across the four twin groups defined by gestational age and chorionicity.

• 143 twin families with 12-month-old infants were enrolled and divided into four groups: dichorionic-diamniotic full-term, dichorionic-diamniotic preterm, monochorionic-diamniotic full-term, and monochorionic-diamniotic preterm.
• Gut microbiota diversity and composition were analyzed via 16S rRNA sequencing.
• 10 group-specific gut microbiota genera were identified across the four groups.
• Wilcoxon's rank-sum tests and generalized estimating equations were used for alpha diversity comparison and differential microbiota identification.

394 differential metabolites were identified across the four twin groups.

• Fecal metabolism was analyzed via untargeted metabolomics.
• 394 differential metabolites were identified among the dichorionic-diamniotic full-term, dichorionic-diamniotic preterm, monochorionic-diamniotic full-term, and monochorionic-diamniotic preterm groups.
• Pathway analysis highlighted three key metabolites: Morphine (isoquinoline alkaloid biosynthesis, drug metabolism, neuroactive ligand-receptor interaction), Nicotinuric acid (nicotinate/nicotinamide metabolism), and Catechin (flavonoid/phenylpropanoid biosynthesis).

Fifty-two microbiota taxa showed genetic variance, but none overlapped with the group-specific taxa identified by gestational age and chorionicity.

• Twin-based ACE models were used to evaluate genetic and environmental contributions to gut microbiota.
• 52 microbiota taxa showed significant genetic variance.
• None of the 52 genetically influenced taxa overlapped with the 10 group-specific genera, suggesting preterm birth and chorionicity effects on gut microbiota are environmentally rather than genetically driven.
• Preterm birth exerts a stronger effect than genetic factors in shaping the gut microbiota of 12-month-old twins.

Six genera and 18 metabolites were correlated with twins' physical and neurobehavioral development.

• Association analyses between gut microbiota/metabolites and developmental outcomes were performed with confounder adjustment.
• Six genera were associated with physical or neurobehavioral development outcomes at 12 months.
• 18 metabolites were correlated with physical or neurobehavioral development outcomes.
• Key metabolic pathways implicated included isoquinoline alkaloid biosynthesis, nicotinate/nicotinamide metabolism, and flavonoid/phenylpropanoid biosynthesis.

Preterm birth was associated with gut microbiota dysbiosis and metabolic perturbations in twins at 12 months of age.

• The study compared dichorionic-diamniotic and monochorionic-diamniotic twin pairs, each stratified by full-term versus preterm birth.
• Preterm birth was identified as a key perinatal factor affecting both gut microbiota composition and fecal metabolome.
• The findings suggest these microbial and metabolic perturbations may affect twin physical and neurobehavioral development.
• The combined impacts of preterm birth and chorionicity on gut microbiota, metabolism, and physical/neurobehavioral development were examined in 143 twin families.