Evaluation of the correlation between fetal well being tests with APGAR score and PH of umbilical artery in high risk pregnant women

Introduction: Acidosis-hypoxic phenomenon is a valid indicator to determine fetal distress and is defined by measuring the blood pH of umblical cord. None of the present screening tests for evaluation of pregnant mothers have acceptable clinical accuracy to assess fetal acidosis. We decided to evaluate the relationship between fetal well being tests Non-Stress Test (NST), Oxytocin Challenge Test (OCT) and Biophysical Profile (BPP) with APGAR score and the blood pH of umblical cord. Methods: In this case-control study, we enrolled 50 high-risk pregnant women (BPP test positive, OCT positive or non reactive NST) as cases and 50 pregnant women without fetal risk factors as control group. The umblical cord blood sample was taken immediately after delivery. Some variables such as maternal age, gestational age, parity, NST, OCT, BPP, blood pH of umblical cord, neonatal weight, sex and APGAR score were evaluated and the data was analyzed by SPSS software. Results: Discrimination between NST with acidosis (P<0.01) was significant in the case and control groups, but in case of OCT with acidosis it was not significant. NST and OCT had low sensitivity (58.3 and 46.5 respectively). Besides, the relationship between BPP and blood pH of umblical cord was significant in the case and control groups (P<0.02). APGAR score of the cases were lower than the control group (P<0.0001). Conclusion: In evaluation of fetal acidosis, the BPP test is the best screening test comparing to NST and OCT.