British Journal of Obstetrics and Gynaecology October 1977. Vol84. p 800
CORRESPONDENCE For intervals from 5 to 12 minutes, the regression equation indicates a decrease of one point of Apgar score for each additional two minutes of operating time. This relationship was not significant for patients without fetal distress. Higher order polynomials (greater than linear) do not improve the correlation significantly. In light of this analysis of the data, the role of fetal monitoring preceding and during Caesarean section is clarified and it would appear that the recommendations for clinical care at the end of Dr Taylor’s paper should be modified. If the fetus is being monitored and there is no evidence of fetal distress, haste between induction of general anaesthesia and delivery may not be necessary, but if there is evidence of fetal distress, prompt
Fetal Heart Rate Monitoring during Caesarean Section. Taylor, A. B. W. (1977): British Journal of Obstetrics and Gynuecology, 84, 281. From: R. J. Sokol Sir, Whether or not the duration of the interval from induction of anaesthesia to delivery affects neonatal outcome has been studied repeatedly. Bonica (1969) cites several studies which indicate that the longer the anaesthesia, the greater the neonatal depression, whereas other studies, such as that of Timor-Tritsch et a1 (1976) and those cited by Taylor (1977), suggest that there is no need for haste.
I TABLE Relationship between Apgar score at one minute and interval between induction of anaesthe sia and delivery in 22 patients delivered under general anaesthesia
Regression equation ~~
All Normal FHR trace Abnormal FHR trace
22 12 10
Apgar = 10.7-0.36 min Apgar = 10.2-0.26 min Apgar = 11.3-0.50 min
fetal heart rate. correlation coefficient.
-0.53 -0.35 -0.81
0.01 NS t0.01
min = minutes. NS = not significant.
Dr Taylor interprets his own results to indicate that the Apgar score at one minute bears no apparent relation to the length of the interval between induction of anaesthesia and delivery. However, visual examination of his Figure 3 suggests that the longer intervals might be associated with lower Apgar scores. This possibility was evaluated by submitting the data to the polynomial regression analysis, the results of which are shown in Table I. Contrary to Dr Taylor’s interpretation, even though the longest interval was a relatively brief 13 minutes, Apgar scores decrease significantly as the interval to delivery increases. Moreover, when patients with abnormal fetal heart rate (FHR) traces are separated from those with other indications for Caesarean section, the Apgar score is seen to be highly negatively correlated with the induction of anaesthesia to delivery interval only for the group with fetal distress (P