Maternal body mass index and the risk of early-onset Group B Streptococcus disease in newborns: A systematic review and meta-analysis

Elisabeth Emanuel Graae; Niels Uldbjerg; Flemming Skjøth; Marie Aunskjær Bech; Pernille Nathalie Nielsen; Susani Rothmann Karkov; Caroline Margaret Moos; Mohammed Rohi Khalil

doi:10.1371/journal.pone.0329423

Maternal body mass index and the risk of early-onset Group B Streptococcus disease in newborns: A systematic review and meta-analysis

Elisabeth Emanuel Graae^*
, Niels Uldbjerg
, Flemming Skjøth
, Marie Aunskjær Bech
, Pernille Nathalie Nielsen
, Susani Rothmann Karkov
, Caroline Margaret Moos
, Mohammed Rohi Khalil

^*Kontaktforfatter

Aarhus Universitetshospital
Aarhus Universitet
Sygehus Lillebælt

Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › peer review

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Abstract

BACKGROUND: Early-onset group B Streptococcus disease (EOGBS) remains a leading cause of neonatal morbidity and mortality. The incidence can be substantially reduced by intrapartum antibiotic prophylaxis in women with defined risk factors. However, the role of high prepregnancy body mass index (BMI) as a risk factor remains unclear. This systematic review and meta-analysis therefore aimed to evaluate the association between maternal BMI and the risk of EOGBS, as well as related proxy outcomes, including intrapartum vaginal GBS colonization and rectovaginal or urinary GBS colonization before term.

METHODS: We systematically searched MEDLINE, Embase, and Cochrane CENTRAL on the 28th of January 2026, for studies examining the relationship between pregestational BMI and EOGBS or its proxy outcomes. Eligible studies included observational and interventional designs but not case reports and conference abstracts. Risk of bias was assessed using the QUIPS tool. Random-effects meta-regression and sensitivity analyses were performed.

RESULTS: We identified 19 eligible observational studies reporting data from a total of 3,707,047 women, encompassing 277,887 cases. For the risk of EOGBS and its proxy outcomes, assuming a log-linear association, our meta-regression showed a 2.4% increase in the odds ratio (OR) per unit increase in BMI. This corresponds to an OR of 1.4 (95% CI 1.1-1.6) for a BMI of 35 and 1.7 (95% CI 1.3-2.3) for a BMI of 45, compared to a normal BMI of 22.3. One very large study on 1,971,346 live singleton births with 780 EOGBS cases, found a hazard ratio of 2.4 (95% CI 1.7-3.4) for a BMI of 35.0-39.9 compared to normal BMI (18.5-24.9).

CONCLUSIONS: Although the overall association appears modest, incorporating BMI may improve prevention strategies for EOGBS .

Originalsprog	Engelsk
Artikelnummer	e0329423
Tidsskrift	PLOS ONE
Vol/bind	21
Udgave nummer	5
Antal sider	21
ISSN	1932-6203
DOI	https://doi.org/10.1371/journal.pone.0329423
Status	Udgivet - 8. maj 2026

Bibliografisk note

Publisher Copyright:
© 2026 Graae et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Finansiering

We thank Jeppe Benneskou Schroll (Center for Evidence-Based Medicine Odense) and Lasse Østengaard (University of Southern Denmark) for their advice on the conceptualization of this systematic review. We also thank Torben Bjerregaard Larsen for guidance on planning the statistical analysis, and Peter Everfelt (Esbjerg and Grindsted Hospital) for initial support with the literature search. The contributors acknowledged here did not participate in the writing of the manuscript or in the decision to submit it for publication, and may not necessarily agree with its content.

Dokumenter og links

10.1371/journal.pone.0329423Licens: CC BY

Open Access VersionForlagets udgivne version, 842 KBLicens: CC BY

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Tjek adgangen til materialet i Syddansk Universitetsbiblioteks søgemaskine

Citationsformater

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abstract = "BACKGROUND: Early-onset group B Streptococcus disease (EOGBS) remains a leading cause of neonatal morbidity and mortality. The incidence can be substantially reduced by intrapartum antibiotic prophylaxis in women with defined risk factors. However, the role of high prepregnancy body mass index (BMI) as a risk factor remains unclear. This systematic review and meta-analysis therefore aimed to evaluate the association between maternal BMI and the risk of EOGBS, as well as related proxy outcomes, including intrapartum vaginal GBS colonization and rectovaginal or urinary GBS colonization before term.METHODS: We systematically searched MEDLINE, Embase, and Cochrane CENTRAL on the 28th of January 2026, for studies examining the relationship between pregestational BMI and EOGBS or its proxy outcomes. Eligible studies included observational and interventional designs but not case reports and conference abstracts. Risk of bias was assessed using the QUIPS tool. Random-effects meta-regression and sensitivity analyses were performed.RESULTS: We identified 19 eligible observational studies reporting data from a total of 3,707,047 women, encompassing 277,887 cases. For the risk of EOGBS and its proxy outcomes, assuming a log-linear association, our meta-regression showed a 2.4\% increase in the odds ratio (OR) per unit increase in BMI. This corresponds to an OR of 1.4 (95\% CI 1.1-1.6) for a BMI of 35 and 1.7 (95\% CI 1.3-2.3) for a BMI of 45, compared to a normal BMI of 22.3. One very large study on 1,971,346 live singleton births with 780 EOGBS cases, found a hazard ratio of 2.4 (95\% CI 1.7-3.4) for a BMI of 35.0-39.9 compared to normal BMI (18.5-24.9).CONCLUSIONS: Although the overall association appears modest, incorporating BMI may improve prevention strategies for EOGBS .",

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T2 - A systematic review and meta-analysis

AU - Graae, Elisabeth Emanuel

AU - Uldbjerg, Niels

AU - Skjøth, Flemming

AU - Bech, Marie Aunskjær

AU - Nielsen, Pernille Nathalie

AU - Karkov, Susani Rothmann

AU - Moos, Caroline Margaret

AU - Khalil, Mohammed Rohi

N1 - Publisher Copyright: © 2026 Graae et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

PY - 2026/5/8

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N2 - BACKGROUND: Early-onset group B Streptococcus disease (EOGBS) remains a leading cause of neonatal morbidity and mortality. The incidence can be substantially reduced by intrapartum antibiotic prophylaxis in women with defined risk factors. However, the role of high prepregnancy body mass index (BMI) as a risk factor remains unclear. This systematic review and meta-analysis therefore aimed to evaluate the association between maternal BMI and the risk of EOGBS, as well as related proxy outcomes, including intrapartum vaginal GBS colonization and rectovaginal or urinary GBS colonization before term.METHODS: We systematically searched MEDLINE, Embase, and Cochrane CENTRAL on the 28th of January 2026, for studies examining the relationship between pregestational BMI and EOGBS or its proxy outcomes. Eligible studies included observational and interventional designs but not case reports and conference abstracts. Risk of bias was assessed using the QUIPS tool. Random-effects meta-regression and sensitivity analyses were performed.RESULTS: We identified 19 eligible observational studies reporting data from a total of 3,707,047 women, encompassing 277,887 cases. For the risk of EOGBS and its proxy outcomes, assuming a log-linear association, our meta-regression showed a 2.4% increase in the odds ratio (OR) per unit increase in BMI. This corresponds to an OR of 1.4 (95% CI 1.1-1.6) for a BMI of 35 and 1.7 (95% CI 1.3-2.3) for a BMI of 45, compared to a normal BMI of 22.3. One very large study on 1,971,346 live singleton births with 780 EOGBS cases, found a hazard ratio of 2.4 (95% CI 1.7-3.4) for a BMI of 35.0-39.9 compared to normal BMI (18.5-24.9).CONCLUSIONS: Although the overall association appears modest, incorporating BMI may improve prevention strategies for EOGBS .

AB - BACKGROUND: Early-onset group B Streptococcus disease (EOGBS) remains a leading cause of neonatal morbidity and mortality. The incidence can be substantially reduced by intrapartum antibiotic prophylaxis in women with defined risk factors. However, the role of high prepregnancy body mass index (BMI) as a risk factor remains unclear. This systematic review and meta-analysis therefore aimed to evaluate the association between maternal BMI and the risk of EOGBS, as well as related proxy outcomes, including intrapartum vaginal GBS colonization and rectovaginal or urinary GBS colonization before term.METHODS: We systematically searched MEDLINE, Embase, and Cochrane CENTRAL on the 28th of January 2026, for studies examining the relationship between pregestational BMI and EOGBS or its proxy outcomes. Eligible studies included observational and interventional designs but not case reports and conference abstracts. Risk of bias was assessed using the QUIPS tool. Random-effects meta-regression and sensitivity analyses were performed.RESULTS: We identified 19 eligible observational studies reporting data from a total of 3,707,047 women, encompassing 277,887 cases. For the risk of EOGBS and its proxy outcomes, assuming a log-linear association, our meta-regression showed a 2.4% increase in the odds ratio (OR) per unit increase in BMI. This corresponds to an OR of 1.4 (95% CI 1.1-1.6) for a BMI of 35 and 1.7 (95% CI 1.3-2.3) for a BMI of 45, compared to a normal BMI of 22.3. One very large study on 1,971,346 live singleton births with 780 EOGBS cases, found a hazard ratio of 2.4 (95% CI 1.7-3.4) for a BMI of 35.0-39.9 compared to normal BMI (18.5-24.9).CONCLUSIONS: Although the overall association appears modest, incorporating BMI may improve prevention strategies for EOGBS .

U2 - 10.1371/journal.pone.0329423

DO - 10.1371/journal.pone.0329423

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C2 - 42102051

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SN - 1932-6203

VL - 21

JO - PLOS ONE

JF - PLOS ONE

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M1 - e0329423

ER -

Maternal body mass index and the risk of early-onset Group B Streptococcus disease in newborns: A systematic review and meta-analysis

Abstract

Bibliografisk note

Finansiering

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SDU link

Fingeraftryk

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