Meconium staining of the liquor in a low-risk population

Although the significance of meconium-stained amniotic fluid as a sign of fetal distress remains controversial, its presence remains a concern to both obstetricians and neonatologists since signs of asphyxia and meconium staining are associated with an increase in perinatal morbidity and mortality. The aim of this study was to evaluate the role of meconium staining of the liquor in the low-risk obstetric population in terms of fetal distress and perinatal morbidity and mortality. In a prospective cohort study at a referral hospital and at one of two municipal clinics, women with a singleton pregnancy of 37 to 42 weeks gestation and with no pre-defined risk factor were recruited into the study. Study patients comprised those with meconium staining of the liquor and controls comprised similar women but with clear liquor. Meconium staining of the liquor was associated with poor outcome in all the outcome measures assessed. Fetal heart rate (FHR) abnormality was more closely associated with adverse outcome than meconium staining, and thin meconium alone was not associated with any adverse outcome except respiratory distress. Women with thin meconium in the presence of normal FHR can therefore be safely managed at the clinic level. Thick meconium itself was a risk factor for poor outcome, more so if associated with FHR abnormality, and should be an indicator for early referral.