Umbilical cord arterial blood base excess as gold standard for foetal well being screening test validity at term delivery.
OBJECTIVE
To assess the validity of cardiotocography and meconium staining of amniotic fluid, as a predictor of neonatal acidaemia.


METHODS
It was a cross sectional analytical study, carried out at a tertiary care private hospital from 1st Jan 2006-31st Dec 2006. After due exclusion 122 cords samples were selected for study. Classification of foetal heart patterns were from FIGO-Guidelines (1987) and grading of meconium staining of amniotic fluid as thin, moderate and thick on subjective assessment. Cord samples collected at birth and subsequent analysis was usually achieved within 30 minutes of delivery.


RESULTS
Total deliveries during the study period were 960. One hundred and twenty two (12.7%) cord results were studied. Umbilical cord arterial base excess (> or = 12 mmol/L) at birth was used as gold standard to determine the validity of cardiotocography and meconium staining of amniotic fluid. Validity tests of cardiotocography: Sensitivity 15.38%, Specificity 86%, Positive predictive value 11.76%. Negative predictive value 89%. Validity tests of meconium staining of amniotic fluid: Sensitivity 18.75%, Specificity 79.2%, Positive predictive value 12%, Negative predictive value 86%.


CONCLUSIONS
Electronic foetal monitoring (cardiotocography) is an objective assessment of foetal well being. Normal reactive trace correlates highly with absence of acidaemia at birth. However cardiotocography alone is not a diagnostic test for detecting foetal distress. Similarly clear liquor is an indication of foetal well being and meconium staining of amniotic fluid is not always associated with an ill infant.
Gynae Unit-IV, Dow University of Health Sciences, Karachi.
Shakira
S
Parveen
D000138:Acidosis / Q000097:blood / Q000175:diagnosis*; D000328:Adult; D000653:Amniotic Fluid; D015148:Cardiotocography; D003430:Cross-Sectional Studies; D005260:Female; D005312:Fetal Blood / Q000737:chemistry*; D005323:Fetal Monitoring; D005865:Gestational Age; D006340:Heart Rate, Fetal; D006801:Humans; D007231:Infant, Newborn; D008470:Meconium / Q000737:chemistry*; D010154:Pakistan; D011247:Pregnancy; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D055815:Young Adult