Abnormal labour: an evidence-based approach

Group B streptococci (GBS) are bacteria that colonise the genital tract in a significant proportion of pregnant women. Bacteriological screening of the low vagina is positive in 22% of women but this figure increases to 27% if the rectum is also swabbed. Early-onset GBS sepsis in the neonate is associated with significant morbidity and mortality. GBS infection is more likely following prolonged rupture of the membranes, and intrapartum antibiotic prophylaxis significantly reduces the incidence of early-onset neonatal sepsis. Secondary arrest of labour occurs in 6% of nulliparous women and 2% of multiparous women. One of the causes of secondary arrest is an occipitoposterior position. Breech presentation is associated with higher rates of perinatal morbidity and mortality. External cephalic version reduces the incidence of noncephalic presentation. This article describes three case scenarios highlighting these problems, and provides a rational clinical approach to them based on available evidence.