Low amniotic fluid index in high-risk pregnancy and poor apgar score at birth

To determine the accuracy of antepartum Amniotic Fluid Index (AFI) of < or = 5 cm as a predictor of adverse outcome at birth in high-risk pregnancies.

Cross-sectional study.

Obstetrics and Gynaecology Unit I, Holy Family Hospital and Railway Teaching Hospital Complex, Rawalpindi, from February 2003 to January 2004.

One hundred pregnant women at term gestation were studied. Each high-risk woman at term with an AFI of < or = 5 cm admitted for delivery through emergency or outpatient department was labeled as predictor of poor outcome. The next high-risk pregnant woman at term with the same pregnancy complication but an AFI of > 5 cm was labeled as predictor of good outcome at birth. The subjects in both the groups were demographically matched and fulfilled the inclusion and exclusion criteria. The Apgar score was calculated at 5 minutes of birth. The newborns, with Apgar score < or = 6 at 5 minutes of birth were labeled as diseased and > 6 were labeled as healthy. AFI was compared with Apgar score, using Chi-square and a p-value was calculated to determine the statistical significance. Sensitivity, specificity, efficiency and the predictive values of AFI at a cut off point of < or = 5 cm as a predictor of adverse outcome at birth (Apgar score of < or =6 at 5 minutes of birth) in high-risk pregnancy were calculated.

Only 8 neonates of 50 women with low AFI had low Apgar score. Similarly, 6 neonates of 50 women with normal AFI had poor Apgar score. The diagnostic sensitivity, specificity, positive predictive value, negative predictive value and efficiency of AFI as test were 57.1%, 51.3%, 16%, 88% and 52% respectively.

Low AFI is a poor predictor of adverse outcome for high-risk term patients. AFI is not a good screening test for high-risk pregnant women at term for birth of an infant with low Apgar score.