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. 2021 Apr;47(4):1305-1311.
doi: 10.1111/jog.14652. Epub 2021 Jan 12.

iPREFACE score: Integrated score index to predict fetal acidemia by intrapartum fetal heart rate monitoring

Ayumu Ito  1   2   3 , Eijiro Hayata  2 , Masahiko Nakata  1   2 , Ayako Oji  2 , Takamasa Furukawa  3 , Masahito Nakakuma  3 , Mineto Morita  1   2
Affiliations

iPREFACE score: Integrated score index to predict fetal acidemia by intrapartum fetal heart rate monitoring

Ayumu Ito et al. J Obstet Gynaecol Res. 2021 Apr.

Abstract

Aim: Cardiotocography is used worldwide to evaluate fetal well-being during pregnancy and labor. In past guidelines, the management plan was determined based on the assessment of the most severe waveform. There are no guidelines for evaluating the integrated recurrent decelerations; however, we believe their assessment to be essential for predicting the status of the fetus. The objective of this study was to propose an indicator for performing medical interventions during labor by creating a scoring system that reflects integrated recurrent decelerations.

Methods: In this retrospective cohort study, we included data for only full-term single fetus births from vaginal deliveries. The score named the iPREFACE score (integrated score index to predict fetal acidemia by intrapartum fetal heart rate monitoring) was calculated using cardiotocography findings from continuing 30 min before delivery. We examined the iPREFACE score and fetal acidemia association and calculated the cut-off iPREFACE scores for acidemia using receiver operating characteristic curves.

Results: The study included 469 delivery cases. Their iPREFACE scores exhibited a significant negative correlation with the umbilical artery blood pH (correlation coefficient; -0.43). The cut-off iPREFACE scores for the umbilical artery blood with pH <7.20, <7.10 and <7.0 were 44, 46 and 67, respectively (the areas under the curve were 0.776, 0.962 and 0.996, respectively).

Conclusion: The iPREFACE score may predict fetal acidemia and could be used as an indicator for timely medical interventions during labor. Because assessments using a cardiotocography are quick and easy to perform, the iPREFACE score could be a valuable tool in clinical practice.

Keywords: CTG; cardiotocography; electronic fetal monitoring; hypoxic-ischemic encephalopathy; umbilical artery blood pH.

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Figures

Figure 1
Figure 1
Risk levels of the 5‐tier classification as defined by the Japanese Society of Obstetrics and Gynecology.
Figure 2
Figure 2
Example of scoring the iPREFACE score. iPREFACE, integrated score index to predict fetal acidemia by intrapartum fetal heart rate monitoring; MVD, mild variable deceleration; SVD, severe variable deceleration; SLD, severe late deceleration; SVD, severe prolonged deceleration.
Figure 3
Figure 3
Study participants' selection flowchart.
Figure 4
Figure 4
Regression line between iPREFACE score and umbilical artery blood gas pH. iPREFACE, integrated score index to predict fetal acidemia by intrapartum fetal heart rate monitoring, pH, a pH: the numerical measure of acidity and alkalinity of a solution.
Figure 5
Figure 5
ROC curve comparisons for acidemia. (a) pH < 7.2, (b) pH < 7.1, (c) pH < 7.0. iPREFACE, integrated score index to predict fetal acidemia by intrapartum fetal heart rate monitoring. AUC, area under the curve; ROC, receiver operating characteristic.
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