Significance of Meconium-Stained Liquor on Neonatal Outcome

Abstract

Background: Meconium-stained amniotic fluid is encountered in 12-20% of term deliveries and remains controversial regarding its true significance. The differentiation between thin and thick meconium is especially controversial, and there is a lack of prospective data comparing outcomes based on consistency. The aim of this study was to assess the significance of MSAF on neonatal outcome, comparing clear amniotic fluid, thin meconium and thick meconium groups.

Methods: A prospective cohort study was conducted in the department of Gynaecology and Obstetrics and the Neonatal Intensive Care Unit, Moulvi Ameer Shah Memorial Hospital, Peshawar, Pakistan for the duration from from January 2025 to December 2025 and included 110 term singleton pregnancies. Amniotic fluid at rupture of membranes was classified as clear (n=37), thin meconium (n=36), and thick meconium (n=37). Primary outcomes were the rate of meconium aspiration syndrome (MAS), need for positive pressure ventilation (PPV), and neonatal encephalopathy. Data were analyzed using chi-square, ANOVA and logistic regression.

Results: MSAF incidence was 66.4%. MAS occurred exclusively in the thick meconium group (51.4%, n=19). PPV was required in 83.8% of thick meconium cases versus 16.7% in thin meconium and 0% in clear cases (p<0.001). Neonatal encephalopathy occurred in 27.0% of thick meconium cases. Thick meconium was the strongest independent predictor of MAS (OR 48.2, p<0.001) and neonatal encephalopathy (OR 22.5, p<0.001). Thin meconium did not show a significant increased risk of MAS or encephalopathy as compared to clear fluid.

Conclusion: Thick meconium is an important predictor of poor neonatal outcome, MAS, acidemia and encephalopathy. The risk of adverse neonatal outcome with thin meconium is minimal in the absence of fetal heart rate abnormalities. These findings support a stratified approach to the management of MSAF based on the consistency of meconium.