Korean J Obstet Gynecol.  2003 Mar;46(3):514-521.

Approximate Entropy of the Short-term Variability of Fetal Heart Rate as an Efficient Measurement of Fetal Distress

• Choi EJ
• Chung DY
• Shim YB
• Yi SH
• Lew CS
• Lee JH
• Shin JC
• Ahn HY
• Kim SP

Abstract

OBJECTIVE
The purpose of this study was to evaluate the usefulness of approximate entropy on fetal heart rate variability of electronic fetal monitoring taken during antepartum and intrapartum periods as a new diagnostic method of fetal distress.
METHODS
Among 76 pregnant women who underwent computerized electronic fetal monitoring and cord blood gas analysis, we divided them into 3 groups, i.e.; 36 into normal fetus group, 26 into presumed distress group and 14 into acidemic distress group. We performed a frequency analysis on time series of heart rate variability in three groups. In order to perform non-linear analysis on the raw data of the fetal heart rate, after resampling and low pass filtering, we investigated approximate entropy.
RESULTS
The results of the approximate entropy showed that the value in normal fetus group was significantly high than the value in distress group. But in the distress group, ApEn value was not difference between acidemic and non-acidemic subgroup. ApEn of HRV was confirmed in nonlinear parameter without low pass filtering and resampling.
CONCLUSION
The results show that the fetal heart rate variability has nonlinear characteristics and could distinguish normal fetal heart rate pattern and distress pattern numerically and objectively. And these ApEn value are useful for prediction and diagnosis of fetal distress in ante and prenatal periods.

Keyword

Distress; Variability; Approximate entropy

MeSH Terms

Ants
Diagnosis
Entropy*
Female
Fetal Blood
Fetal Distress*
Fetal Heart*
Fetal Monitoring
Fetus
Heart Rate
Heart Rate, Fetal*
Humans
Pregnancy
Pregnant Women