Maternal iron deficiency, preterm birth, and disrupted microbial inheritance: a proposed double-hit hypothesis
- 1Department of Obstetrics and Gynecology, Ali Hospital, Islamabad, Pakistan
- 2Rawal Institute of Medical Sciences, Islamabad, Pakistan
Abstract
The maternal microbiome is the infant’s primary microbial inheritance, transmitted mainly through the maternal gut, vaginal delivery, breast milk, and skin-to-skin contact. Maternal iron deficiency (ID), with anemia, is a common and modifiable nutritional condition associated with impaired immune function and increased preterm birth (PTB) risk, whereas evidence for ID without anemia remains limited. It may influence maternal microbial ecology; however, its potential effect on maternal-to-infant microbial transmission remains unexplored. This review, conducted across PubMed, Embase, and Web of Science (January 2000–June 2026), proposes a double-hit hypothesis defined by the source and biological context of disruption rather than by a strictly temporal sequence. The first hit comprises potentially altered maternal-origin microbial and immunologic inputs from the vaginal, gut, and breast milk ecosystems; the second hit comprises PTB and neonatal intensive care (NICU)-associated disruption of early microbial succession. Human evidence directly linking ID to vaginal dysbiosis is limited to a single study, evidence relating maternal iron status to milk lactoferrin is inconsistent, and the contribution of vaginal communities to persistent infant gut colonization remains uncertain whereas vaginal exposure may have transient ecological or immunologic effects. No study has simultaneously evaluated maternal iron biomarkers, vaginal community state type (CST), breast milk composition, maternal gut microbiome and longitudinal infant gut microbiota. The proposed framework is therefore hypothesis-generating and identifies testable pathways through which maternal ID may alter maternal microbial and immunologic inputs, while also being associated with an increased risk of PTB. PTB, together with the resulting prematurity-related vulnerability and subsequent postnatal exposures, may further disrupt early infant microbiome development.
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BibTeX
@article{khan2026maternal,
title = {{Maternal iron deficiency, preterm birth, and disrupted microbial inheritance: a proposed double-hit hypothesis}},
author = {Fouzia Zahid Ali Khan and Syed Arham Ali},
journal = {Frontiers in Cellular and Infection Microbiology},
year = {2026},
month = oct,
doi = {10.3389/fcimb.2026.1953925},
url = {https://doi.org/10.3389/fcimb.2026.1953925},
note = {CC BY},
}
RIS
TY - JOUR
TI - Maternal iron deficiency, preterm birth, and disrupted microbial inheritance: a proposed double-hit hypothesis
AU - Fouzia Zahid Ali Khan
AU - Syed Arham Ali
PY - 2026
DA - 2026/10/23
JO - Frontiers in Cellular and Infection Microbiology
DO - 10.3389/fcimb.2026.1953925
UR - https://doi.org/10.3389/fcimb.2026.1953925
AB - The maternal microbiome is the infant’s primary microbial inheritance, transmitted mainly through the maternal gut, vaginal delivery, breast milk, and skin-to-skin contact. Maternal iron deficiency (ID), with anemia, is a common and modifiable nutritional condition associated with impaired immune function and increased preterm birth (PTB) risk, whereas evidence for ID without anemia remains limited. It may influence maternal microbial ecology; however, its potential effect on maternal-to-infant microbial transmission remains unexplored. This review, conducted across PubMed, Embase, and Web of Science (January 2000–June 2026), proposes a double-hit hypothesis defined by the source and biological context of disruption rather than by a strictly temporal sequence. The first hit comprises potentially altered maternal-origin microbial and immunologic inputs from the vaginal, gut, and breast milk ecosystems; the second hit comprises PTB and neonatal intensive care (NICU)-associated disruption of early microbial succession. Human evidence directly linking ID to vaginal dysbiosis is limited to a single study, evidence relating maternal iron status to milk lactoferrin is inconsistent, and the contribution of vaginal communities to persistent infant gut colonization remains uncertain whereas vaginal exposure may have transient ecological or immunologic effects. No study has simultaneously evaluated maternal iron biomarkers, vaginal community state type (CST), breast milk composition, maternal gut microbiome and longitudinal infant gut microbiota. The proposed framework is therefore hypothesis-generating and identifies testable pathways through which maternal ID may alter maternal microbial and immunologic inputs, while also being associated with an increased risk of PTB. PTB, together with the resulting prematurity-related vulnerability and subsequent postnatal exposures, may further disrupt early infant microbiome development.
SN - 2235-2988
ER -