Predictive Value Of Meconium Stained Amniotic Fluid In Diagnosis Of Fetal Acidosis

Abstract

Introduction Although the finding of meconium stained amniotic fluid in labor is clinically significant, meconium per se is not a strong predictor of intrapartum fetal acidosis. Umbilical cord arterial blood gas analysis performed immediately at birth is the most objective way of determining fetal/newborn oxygenation status during labor and shortly before birth and can give a guide on the level of ongoing neonatal care required. Objective To use umbilical cord artery blood gas analysis (ABG) to evaluate the diagnostic accuracy of intrapartum presence of meconium staining of amniotic fluid to diagnose fetal acidosis/ fetal distress. Study site Kenyatta National Hospital Labour ward Study Design Prospective Cohort study. Materials Umbilical cord arterial blood drawn immediately at birth from a clamped segment of the cord into a 2 cc syringe already flushed with one drop of heparin. The blood was transported immediately for blood gas analysis at the hospital intensive care unit where the analyzer is located. Bayer Diagnostics model 348 blood gas analyzer was used. Sample size: One hundred (100) newborn umbilical cord arterial blood samples were analyzed; 50 as exposed to meconium stained amniotic fluid (MSAF) in labor and 50 as unexposed to meconium stained amniotic fluid in labour. Duration of study This was a prospective study that was conducted between June 2008 and November 2008 both months inclusive. Results Findings of newborn acidosis was slightly high among meconium stained amniotic fluid (MSAF) as compared with those with clear liquor (38 per cent versus 20 per cent) (OR-2.5, 95% Confidence Interval 1.0-6.0, p=0.05).There was no statistical difference of acidosis between the two groups. Meconium stained amniotic fluid is associated with increased caesarean section rates P= 0.0001 A low Apgar score below 6 at one minute was associated with finding of newborn acidosis on umbilical cord arterial blood acid base gas analysis. (Of the ten who had Apgar less than six, 90% had pH below 7.2). Severe acidosis with pH below 6.9 and attended Apgar score below 7 was associated with increased rate of need for resuscitation, admission to newborn unit and perinatal morbidity.