Nonreassuring fetal heart rate decreases heart rate variability in newborn infants.
BACKGROUND
Nonreassuring fetal status (NRFS) refers to a compromised fetal condition which implies hypoxia. The influence of intrapartum hypoxia on autonomic nervous system function in early postnatal life is unknown. This study explored the influence of NRFS on the heart rate variability (HRV) of newborn infants.


METHODS
Singleton newborn infants delivered through Cesarean delivery (CD) with indications of elective purpose (n = 32), dystocia (n = 29), or NRFS (n = 22), and through vaginal birth (VB) (n = 80) were consecutively collected. HRV parameters including standard deviation of average NN intervals (SDANN), low frequency (LF), high frequency (HF), LF%, HF%, and total power (TP), were obtained for analysis in 3 days postpartum. An independent t-test or one-way ANOVA was used to compare differences in numeric data.


RESULTS
SDANN, HF, HF%, and TP of newborn infants in the VB group were significantly higher than those in the CD group. The NRFS group had significantly lower SDANN, HF, and TP than those of the elective group, and significantly lower HF, HF%, and TP than those of the dystocia group.


CONCLUSIONS
Newborn infants delivered through Cesarean section had lower HRV, especially those who experienced NRFS during labor. The long-term effects of changes of HRV in neonates require further evaluation.
Department of Obstetrics and Gynecology, Yuan's General Hospital, No. 162, Chenggong 1st Rd., Kaohsiung 802, Taiwan.
Tzong-Chyi
TC
Sheen
Ming-Huei
MH
Lu
Mei-Yu
MY
Lee
Su-Ru
SR
Chen
D000704:Analysis of Variance; D001341:Autonomic Nervous System / Q000503:physiopathology*; D015148:Cardiotocography / Q000379:methods*; D002585:Cesarean Section / Q000379:methods / Q000706:statistics & numerical data; D036861:Delivery, Obstetric / Q000379:methods / Q000706:statistics & numerical data; D005260:Female; D005316:Fetal Distress / Q000175:diagnosis* / Q000503:physiopathology*; D006340:Heart Rate, Fetal / Q000502:physiology*; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D011247:Pregnancy
electronic fetal monitor; heart rate variability; newborn infants; nonreassuring fetal status