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. 2025 May 22;25(1):599.
doi: 10.1186/s12884-025-07695-w.

Group B Streptococcus maternal colonization and neonatal sepsis in Belgium between 2012 and 2021: a description of the epidemiological situation and identification of risk factors

Zsófia Bognár  1   2 , Charlotte Leroy  3 , Virginie Van Leeuw  3 , Régine Goemaes  4 , Pierrette Melin  5 , Cécile Meex  5 , Rosalie Sacheli  5 , Fleur Camfferman  4   6 , Amber Litzroth  7 , Frederik De Keersmaeker  7 , Laura Cornelissen  7
Affiliations

Group B Streptococcus maternal colonization and neonatal sepsis in Belgium between 2012 and 2021: a description of the epidemiological situation and identification of risk factors

Zsófia Bognár et al. BMC Pregnancy Childbirth. .

Abstract

Background: Group B Streptococcus (GBS) infection is a leading cause of neonatal morbidity. Maternal rectovaginal GBS colonization is a primary risk factor for early onset neonatal GBS infection. In Belgium, pregnant women are screened and, if positive or at risk of transmission, offered intrapartum antibiotic prophylaxis (IAP). We aimed to provide the first comprehensive overview of Belgian data and identify possible risk factors of maternal GBS colonization and neonatal infection.

Methods: We calculated proportions of maternal screening, colonization and incidence of all neonatal GBS infections and identified their risk factors using log binomial regression from national registries' data between 2012-2021.

Results: Of all women, 90.2% were screened and of them, 18.5% were GBS colonized. These proportions were stable over time. Risk factors for maternal GBS colonization included Sub-Saharan (aRR = 1.45, [1.41-1.48]) and North-African origin (aRR = 1.31, [1.28-1.34]) and 5 + parity (aRR = 1.21, [1.18-1.25]). Neonatal GBS sepsis incidence showed a gradually decreasing trend in two individual data sources. Flanders' overall neonatal GBS sepsis estimates were around 0.49 cases per 1000 livebirths. Risk factors for neonatal GBS infection included preterm birth (aRR = 7-41, depending on level of prematurity) and very low birthweight (aRR = 14.83, [6.48-33.94]). Babies of colonized women were at higher risk without (aRR = 7.05, [5.05-9.85]) than with IAP (aRR = 4.34, [3.28-5.74]) compared to non-colonized women.

Conclusions: The maternal colonization rate and the neonatal GBS sepsis incidence in Belgium is comparable to European data. We identified already known risk factors and effectiveness of IAP. Mothers at risk for GBS colonization and premature/low birth weight deliveries could benefit most from additional maternal vaccination strategy.

Keywords: Belgium; Group B streptococcus (GBS); Maternal GBS colonization; Neonatal GBS infection; Neonatal sepsis; Pregnancy; Risk factors.

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Conflict of interest statement

Declarations. Ethics approval and consent to participate: This study was conducted in accordance with the ethical principles outlined in the Declaration of Helsinki. All data accessed in the context of the present study had been previously collected as part of the routine data collection for epidemiological surveillance and national statistics. In accordance with article 9 of the Royal Decree of 14/07/1999 on yearly birth statistics, these data can be used for further research purposes. Therefore, our study was not submitted to a local ethics committee or institutional review board (IRB) because the need for ethical approval was deemed unnecessary according to national regulations. Following article 6, §1, (e) of the General Data Protection Regulation, no written informed consent from the patients is required for the collection and analysis of epidemiological data when the processing of data is necessary for the performance of a task carried out in the public (health) interest. No additional data was collected for the sole purpose of this study, and we used only non-identifiable pseudonymized data. Therefore, the need for consent to participate in this study was deemed unnecessary. Consent for publication: Not applicable. Competing interests: The authors declare no competing interests.

Figures

Fig. 1
Fig. 1
Overall bacterial neonatal sepsis and GBS neonatal sepsis incidence (based on ICD-10 coding), Belgium, 2016-2021, (N=5580, n=543), data source: Minimal Hospital Data
Fig. 2
Fig. 2
Neonatal GBS incidences/notification rates from different data sources, Belgium, 2012-2020/21, data source: Minimal Hospital Data, National Reference Center for Group B Streptococcus, Belgian Birth Register in Flanders
See this image and copyright information in PMC

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