British Journal of Obstetrics and Gynaecology September 1992, Vol. 99 with the choice of local women. All epidurals are managed by the resident anaesthetist. Midwives in Aberdeen are not allowed to administer top-up injections nor control the infusion rate. Similarly because of the local cultural preferences it is not standard practice to let the epidural wear off in the second stage. These details were left out of the paper in favour of brevity. Johnson’s paper (1972) was published in the early days of the controversy over the degree of motor function impairment with different types of conduction anaesthesia. It is useful in that it summarizes in one paper the effect on uterine activity of different types of conduction anaesthesia, using each patient as her own control. Despite the progress in obstetric anaesthesia since then Bates et a/. (1985) reported significantly lower uterine activity integral in women with epidural. (In Reference 7 quoted above there is no mention of how uterine contractility was measured, if at all). Furthermore, Thorp et a/. (1989) in a controlled study designed specifically to analyse the influence of epidural on caesarean section rates for dystocia in nulliparous women showed significantly increased rates in women with epidural analgesia even after correction for selection bias and controlling for confounding variables. Notwithstanding individual assertions, based largely on one’s perceived effects of epidural analgesia, at present there is no good evidence that epidurals do not increase operative delivery rates. Though the use of low concentration, high volume epidural injections and infusions may have lowered the instrumental delivery rates (compared to earlier epidural regimes) these are still higher than in patients receiving conventional or no analgesia and there is still much uncertainty about the optimal concentration or infusion rates of bupivacaine. Kay Dickersin’s review of available literature attempts to put matters into perspective (Dickersin 1989). The decision to do a caesarean section involves an interplay of many factors, not all of which are measureable, particularly in a retrospective study. We therefore examined those factors which might have contributed to the decision to do a casarean section and could also be objectively abstracted from the case records (thus minimizing observer bias). Having excluded patients with medical or obstetrical complications from our study we feel that self selection (for pain relief) was the main criteria for patients receiving epidural analgesia. The personal opinion of the medical staff may have influenced this decision but was impossible to quantify. The epidural and non-epidural groups in our study did not show any significant difference for any of the salient features studied except for cervical dilatation at admission. The possible influence of this difference has been alluded to in our discussion. We reiterate that in the absence of a prospective randomized controlled trial, we have endeavoured to decipher as much as one can from a retrospective study of the possible association between epidural analgesia and breech delivery. Yogesh C. Chadha T. A. Mahmood M. J. Dick N. C. Smith D. M. Campbell A. Templeton Department of Obstetrics and Gynaecology Aherdeen Maternity Hospital Aherdeen

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Thorp J. A., Parusi V. M., Boylan P. C. & Johnston D. A. (1989). The effect of continuous epidural analgesia on caesarean section for dystocia in milliparous women. Am .IObstet Gynaecol, 161, 670-675.

ST-waveform analysis of the fetal electrocardiogram could reduce fetal blood sampling Dear Sir, I enjoyed the paper showing that ST waveform analysis of the fetal electrocardiogram (FECG) could reduce the load of fetal blood sampling (Johanson et a/. 1992). We are conducting a trial of prospective monitoring of high risk labours using ST analysis of the FECG (STan, recorder Cinventa AB, Sweden). Monitoring is started as soon in labour as a single helix fetal scalp electrode (Corometrics) can be applied. The consenting and informed women are randomized into two groups: the first are monitored by conventional cardiotocography (CTG) with a Hewlitt Packard 80300A or 8041A and the FECG is concealed from clinicians; the second group are monitored with CTG and FECG ST waveform analysis. In the first group a fetal blood sampling (FBS) is performed as indicated. In the second group an FBS is performed only if the T/QRS ratio is abnormal, i.e. >0.25 (Arulkumaran et a/. 1990). In the pilot study there was a ten-fold reduction in the use of FBS when this was performed only when the T/QRS ratio was abnormal. Intrapartum acidosis was detected in only one baby who was in the control (CTG) group with a normal T/QRS ratio. Delivery was expedited by forceps; the cord pH was 7.27 with a base deficit of (11 mmol/l), showing a baby with an acid base balance consistent with the normal T/QRS ratio. In all other cases the T/QRS ratio would have correctly reassured the obstetrician of the normal acid base status of the fetus. I believe that prospective monitoring of the FECG using ST analysis can reduce fetal blood sampling. Acidosis will not always be detected by a normal T/QRS ratio