Hypoxia index in the prediction of abnormal CTG at delivery in uncomplicated pregnancies.

OBJECTIVES: The evaluation of hypoxia index (HI) in the prediction of abnormal fetal heart rate at delivery in uncomplicated pregnancies.

MATERIAL AND METHODS: The study group included 148 pregnant patients at term (69 patients with and 79 without brain sparing effect). The value of C/U ratio and HI was determined. Next, its value in predicting abnormal fetal heart rate during labor was evaluated. Then the predictive value of the HI index, C/U and last abnormal values of PI and RI in the MCA and the UA were compared in relation to the analyzed parameters. Evaluation included signs of fetal distress in CTG and abnormal fetal outcome. Then selected parameters, characterizing pregnancy course and fetal outcome with abnormal Doppler indices, were compared.

RESULTS: The designated value of hypoxia index characterized by abnormal neonatal outcome was >10 for sHI and >14 for HI. Low prognostic value of MCA PI and RI, and UA PI and RI has been shown. The highest predictive value was marked by C/U and HI. There were no statistically significant differences in prediction of abnormal fetal heart rate during labor between C/U ratio, HI and sHI.

CONCLUSIONS: The C/U ratio showed the highest sensitivity in the prediction of fetal abnormal heart rate. The C/U ratio, as a easier test, should be recommended as a first-line test in the prediction of abnormal CTG recordings in uncomplicated pregnancies.