Table 1

Delivery and maternal characteristics during successive group B streptococcus (GBS) prevention periods targeting women for intrapartum prophylaxis based on risk factors (prescreening and postscreening) or antenatal screening

VariablePrescreening
2009 to 2013
(n=25 073)
Screening
2014 to 2015
(n=9801)
Postscreening
2016 to 2017
(n=5035)
p Value
Median gestation (weeks)±SD39.1±2.139.1±2.039.2±1.7<0.001
Mode of delivery
 Caesarean7163 (28.6%)2909 (29.7%)1523 (30.3%)0.04
 Instrumental3162 (12.6%)1235 (12.6%)605 (12.0%)
Spontaneous vaginal14 748 (58.8%)5657 (57.7%)2907 (57.7%)
Median age (years)±SD29.0±5.429.6±5.330.2±5.4<0.001
Ethnicity
 Black3401 (13.6%)950 (9.7%)419 (8.3%)<0.001
 British/Irish2665 (10.6%)849 (8.7%)408 (8.1%)
 White other4964 (19.8%)2596 (26.5%)1538 (30.6%)
 Indian Subcontinent11 811 (47.1%)4593 (48.9%)2260 (44.9%)
 Other2232 (8.9%)813 (8.3%)407 (8.1%)