Use of Cardiotocogram (CTG) as an Admission Test as a Predictor of Foetal Outcome in Labour in Low Risk Group

BACKGROUND Intrapartum foetal morbidity and mortality is not uncommon in a low risk population. Any foetus has the potential risk of intrapartum hypoxia which may lead to birth injury. CTG as admission test can be used in low risk pregnant women as an alternative to continuous electronic foetal monitoring. We wanted to evaluate the role of Cardiotocogram (CTG) as admission test in intrapartum low risk pregnant women and to predict foetus at risk of adverse outcome. METHODS This is a prospective observational study which included 200 low risk pregnant women with >37 weeks of gestation in labour. All 200 pregnant women were subjected to admission test (AT) using Sonicaid foetal monitor for 20 minutes. The trace thus obtained was classified as normal, suspicious and pathological AT as per NICE guidelines.' Admission test results were compared with various labour outcome variables i.e., incidence of foetal distress, mode of delivery, neonatal outcome in relation to AT result. Statistical analysis is done using chi square test and p value of <0.01 is taken as statistically significant. RESULTS Out of 200 patients, 164 (82%), 20 (10%) and 16 (8%) had normal, suspicious and pathological admission test result respectively. The incidence of foetal distress (100% Vs 7.92%), caesarean section rate (100% Vs 7.3%), low Apgar score at 5' (50% Vs 4.87%), NICU admission (50% Vs 4.87%) was higher in pathological AT group than in normal AT group. There was one neonatal death in pathological admission test group. Sensitivity, Specificity, PPV, NPV and over all diagnostic accuracy was 54.45%, 92%, 69%, 93% and 83% respectively. CONCLUSIONS Admission test in this study had low sensitivity but high specificity. High specificity in predicting foetus at risk of foetal distress, supports its use as admission test in low risk pregnant women. Early intervention in pathological admission test group reduced the incidence of neonatal morbidity inspite of low sensitivity in detecting distressed foetus. Specificity of 92% and NPV of 93% supports its role as admission test in low risk pregnant women.