Individual and joint association of maternal and cord blood mitochondrial DNA heteroplasmy and copy number with preterm birth.

Authors

Xueqi Qu, Xiumei Hong, Guoying Wang, Jessica An, Jing Sun, Ashley Song, Hilary J Vernon, Xiaobin Wang

Published in

Pediatric research. Jul 16, 2026. Epub Jul 16, 2026.

Abstract

The biological mechanisms underlying preterm birth (PTB) are not fully understood. This study examined the individual and joint associations of mitochondrial DNA (mtDNA) heteroplasmy and copy number (mtDNA-CN) in maternal and cord blood with PTB.
This study analyzed 998 mother-infant dyads (18% PTB). MtDNA heteroplasmy and mtDNA-CN were measured by a targeted DNA sequencing approach using umbilical cord blood collected at birth and maternal blood collected 24-72 hours postpartum. Multivariable logistic regressions were used to evaluate the associations with PTB.
Maternal predicted pathogenic heteroplasmy was associated with a twofold increased risk of PTB (adjusted OR (95% CI) = 2.08 (1.07, 4.05)), whereas no significant associations were observed for maternal overall or functional heteroplasmy. No significant associations were observed for cord blood heteroplasmy measures. A U-shaped association between maternal mtDNA-CN and PTB was observed. Higher cord mtDNA-CN were associated with increased PTB odds (1.36 (1.14, 1.62)). Notably, a significant interaction between maternal and cord mtDNA-CN was found for PTB risk.
Maternal, but not fetal, mtDNA heteroplasmy was associated with increased PTB risk. Both maternal and cord blood mtDNA-CN demonstrated individual and interactive associations with PTB, suggesting that maternal and fetal mitochondrial genomic variations may jointly influence PTB risk.
We found that maternal predicted pathogenic mtDNA heteroplasmy was associated with increased PTB risk; maternal mtDNA-CN showed a U-shaped association with PTB; and higher cord blood mtDNA-CN was positively associated with PTB. This study provides the first evidence from a large birth cohort simultaneously assessing maternal and fetal mtDNA heteroplasmy and mtDNA-CN in relation to PTB, adding a mitochondrial genetics perspective to PTB research. This study highlights mitochondrial genomic variation as a novel pathway in PTB pathogenesis and suggests the potential utility of mtDNA measures as biomarkers for early risk assessment and as a basis for future mitochondria-targeted interventions.

PMID:
42463800
Bibliographic data and abstract were imported from PubMed on 17 Jul 2026.

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