. 2019 Mar 23;9(3):e024324. doi: 10.1136/bmjopen-2018-024324

Table 2.

Estimated early onset GBS (EOGBS) incidence rates in each clinical risk group

Risk group	Input data	Data source
Background incidence/risk group
No risk factors at term	0.2 per 1000 births	Royal College of Obstetricians and Gynaecologists (RCOG), 2012¹⁴
Suspected maternal infection at term	5.29 per 1000 births	RCOG, 2012¹⁴
Pre-term birth	2.30 per 1000 births	RCOG, 2012¹⁴
Suspected maternal infection at pre-term	5.29 per 1000 births	Expert group consensus agreement based on RCOG, 2012¹⁴
Pre-term pre-labour rupture of membranes	2.30 per 1000 births	Expert group consensus agreement based on RCOG, 2012¹⁴
Previous baby with EOGBS with no other risk factors	50 per 1000 births	Expert group consensus agreement
Incidence rate/1000 births
Previous baby with EOGBS with one more additional risk factor	100 per 1000 births	Expert group consensus agreement
Incidental group B Streptococcus detection	2.30 per 1000 births	Expert group consensus agreement based on RCOG, 2012¹⁴
GBS carrier in labour with no other antenatal or intrapartum risk factors, delivering at term	0.91 per 1000 births	Expert group consensus agreement based on available data
GBS carrier in labour with suspected maternal infection, delivering at term	24.0 per 1000 births	Expert group consensus agreement based on available data
Not a GBS carrier in labour, delivering at term (with or without suspected maternal infection)	0 per 1000 births	Expert group consensus agreement
Background colonisation rate
Colonisation rate	22% [Sensitivity analysis: 20%–30%]	Expert group consensus agreement