Impact and risk factors for early-onset group B streptococcal morbidity: analysis of a national, population-based cohort in Sweden 1997-2001.
OBJECTIVE
To study early-onset group B streptococcal (EOGBS) morbidity, mortality, and maternal risk factors.


METHODS
Observational, population-based, retrospective. Data from national registers and medical records.


METHODS
Sweden, 1997-2001.


METHODS
Cohort of 640 infants with a diagnosis of GBS infection out of 435 070 live births.


METHODS
Infants with diagnoses GBS sepsis (P36.0) and/or pneumonia (P23.3) were analysed. In cases with P36.0, register data were validated against infant and maternal medical records. Odds ratios (OR) were estimated by multiple logistic regression.


METHODS
Incidence of EOGBS morbidity, mortality, frequency of maternal risk factors and administration of intrapartum antibiotics.


RESULTS
There were 319 cases with EOGBS sepsis. Blood culture verified 174 cases. There were 145 with clinical sepsis and 180 with pneumonia only. The incidences were 0.40, 0.33, and 0.41 per 1000 live births, respectively. The mortality was 7.5, 0.7, and 2.2% in respective groups. The frequencies of established maternal risk factors were: membrane rupture > or =18 hours, 44%; prematurity, 26%; temperature during labour > or =38 degrees C, 22%. Novel maternal risk factors identified in verified cases were gestational age (GA) of 37 completed weeks (OR 3.5, 1.8-6.5) and gestational diabetes (OR 3.7, 1.8-8.5). When including clinical sepsis, also epidural anaesthesia, infant large for GA, postmaturity, and high maternal age were significant risk factors.


CONCLUSIONS
The incidence of verified EOGBS disease was 0.4 per 1000 live births with a total burden of EOGBS morbidity approximately three times higher. GA of 37 completed weeks and gestational diabetes were identified as additional significant risk factors.
Håkansson
S
S
Department of Pediatrics, University Hospital, Umeå, Sweden. stellan.hankansson@vll.se
Källén
K
K
D000328:Adult; D019072:Antibiotic Prophylaxis; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D018445:Infectious Disease Transmission, Vertical / Q000517:prevention & control*; D011247:Pregnancy; D011251:Pregnancy Complications, Infectious / Q000453:epidemiology*; D011295:Prenatal Care; D012042:Registries; D012189:Retrospective Studies; D012307:Risk Factors; D018805:Sepsis / Q000453:epidemiology; D013290:Streptococcal Infections / Q000453:epidemiology / Q000517:prevention & control / Q000635:transmission*; D013548:Sweden / Q000453:epidemiology