BIRTH 13:4 December 1986

Copyright 0 1986 BIRTH

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ROUNDTABLE: Part 1 1 1 SOME ANSWERS TO QUESTIONS RAISED

ABOUT THE DUBLIN TRIAL

Adrian Grant, D.M., M.R.C.O.G.

In the Dublin trial a hypothesis tested (and sus- tained) was that electronic fetal monitoring (EFM) reduces the risk of neonatal seizures. Only second- ary analyses of the data suggest that this benejit was concentrated in labors of more than 5 hours and those in which oxytocin was used. Claims that EFM is only protective under these conditions, and claims of superior methods of monitoring the fetus or interpreting fetal heart rates tracings, must themselves he tested in formal clinical experiments. (BIRTH 13:4, December 1986)

The most striking finding in the Dublin randomized trial of intrapartum fetal heart rate monitoring (EFM) ( 1 ) was the marked difference between the two trial groups in the number of babies who experi- enced neonatal seizures (12 versus 27). It should be emphasized that the hypothesis that EFM reduces the risk of neonatal seizures was generated before the study from the results of previous randomized trials (2). This hypothesis was subsequently tested and sustained in the Dublin trial. Secondary analy- ses stratified for duration of labor and oxytocin use, in contrast, were not prespecified and should be considered as only hypothesis generating. These secondary analyses suggest that the protective ef- fect of intensive monitoring may be concentrated in cases with labors of more than 5 hours or where oxytocin is used. Long labor and oxytocin use are obviously closely linked, however, and it is not pos- sible to separate them in an analysis of this trial.

The previous trials were all conducted in centers with differing oxytocin policies. Furthermore, oxy- tocin use in the Dublin trial (23 percent) is compara- ble to other centers including many in North Amer- ica (although its use in Dublin is standardized (3)). It is very plausible that some of the protective effect of EFM was against “‘oxytocin-induced asphyxia,” but those who suggesi (4) that electronic monitoring is only protective against oxytocin-induced as- phyxia should now formally test their hypothesis in further prospective clinical experiments.

Similarly, claims that there are superior methods of intrapartum fetal heart monitoring to those evalu- ated in the Dublin trial-whether these are alterna- tive methods of intermittent auscultation ( 5 ) or trac- ing interpretation (6)-should be seen for what they

are: clinical opinions which cannot (so far) be sup- ported with evidence from properly controlled clini- cal experiments.

On the debit side of more intensive intrapartum monitoring, the extra obstetric intervention by ce- sarean and forceps delivery prompted by EFM can have adverse effects on both mothers and babies, and this should be taken into account when consid- ering the role of EFM in clinical practice. In this context an interesting observation in the Dublin trial commented on by Parer (6) was that the three peri- natal deaths in the intensively monitored group due to trauma all followed forceps delivery. In this and in other respects it is important not to read too much into the small number of deaths. Forceps de- livery prompted by “failure to advance” was equally common in the two trial groups and this was the primary indication for forceps delivery in these three electronically monitored traumatic deaths. Rotational forceps delivery is never performed at the National Maternity Hospital in Dublin. Further- more, the trial cases were consistent with a very large study conducted in the hospital which showed that in only 45 percent of cases of tentorial tears associated with forceps delivery is the delivery clas- sified as difficult (7).

It seems plausible that if children suffer long- term disability as a consequence of events during labor they will exhibit abnormal clinical signs in the neonatal period. One component of the long-term follow-up which is currently being conducted in Dublin is the identification at the time of referral to specialist clinics of cases of cerebral palsy amongst children born in the trial. Identification is not yet complete but already it is clear that, as expected, the majority of cases of cerebral palsy did not ex- hibit abnormal neurological signs as neonates. Only a small proportion of cases of cerebral palsy are even potentially preventable by alterations in the management of labor and delivery.

The extent (if any) to which long-term disability may be prevented by more intensive intrapartum fetal heart rate monitoring should be clarified by the other component of long-term follow-up, a review at four years of age of all children who exhibited abnormal neurological signs in the neonatal period. Neonatal seizures are predictive of long-term handi- cap (8). Yet in the Dublin trial, despite the marked difference in the total number of seizure cases in the two trial groups, equal numbers of these babies (3) in each group were found to have severe disabilities

256 BIRTH 13:4 December 1986

at one year of age. One year is too young an age at which to make a judgment about the final status of these children, and we must await the results of the four-year follow-up. Nevertheless, this and other evidence which is reviewed elsewhere (9) does sug- gest that cases of neonatal seizures which are re- lated to obstetrically preventable intrapartum as- phyxia are not those which are associated with disability in childhood.

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REFERENCES

MacDonald D, Grant A , Sheridan-Pereira M, Boylan P, Chalmers I. The Dublin randomized controlled trial of intrapartum fetal heart rate monitoring. Am J Obstet Gynecol 1985; 152:524-39. Chalmers I . Randomised controlled trials of intrapar- tum monitoring. In: Thalhammer 0, Baumgarten KV, Pollak A, eds. Perinatal Medicine. Stuttgart: George Thieme 1979:260-5. O’Driscoll K, Meagher D. Active Munagement of Labour. London: WB Saunders, 1980. Goodlin RC. Is oxytocin the culprit‘? Am J Ohstet Gynecol 1985; 153:928-9. Matthews DD. Fetal monitoring in labour. Br Med J I986;292:826. Parer JT. The Dublin trial of fetal heart rate monitor- ing: the final word? Birth 1986;13:119-121. O’Driscoll K, Meagher D, MacDonald D, Geoghe- gan F. Traumatic intracranial haemorrhage in first born infants and delivery with obstetric forceps. Br J Obstet Gynaecol 1981 ;88:577-81. Dennis J , Chalmers I. Very early neonatal seizure rate: a possible epidemiological indicator of the qual- ity of perinatal care. B r J Obstet Gynaecol

Grant A. The Dublin randomised controlled trial of intrapartum fetal heart rate monitoring (D.M. The- sis]: University of Oxford, 1985.

1982;89:4 18-26.

Adrian Grant is an epidemiologist at the National Perinatal Epi- demiology Unit, Radclqfe Injirrnary, Oxford, England OX2 6HE.

ELECTRONIC MONITORING IN LABOR: TOO GOOD TO BE PUT TO THE TEST?

Marc J.N.C. Keirse, M.D., D.Phil., D.P.H.

Obstetric litigation in the U . S . has rendered elec- tronic fetal monitoring “efjicacious and capable of detecting asphyxia at an early enough stage to avoid neurologic damage.” Court decisions are “directly translatable t o one’s practice” when ran- domized controlled trials, apparently, are not.

Nevertheless, hypotheses regarding the benejits of certain paper speeds and the importance of beat-

to-beat variability cannot be accepted until they are tested in properly designed randomized controlled trials. Among several dfjiculties t o surmount is the repeated jinding that interobserver agreement on fetal heart rate tracings has never exceeded 70 per- cent. (BIRTH 13:4, December 1986)

Obstetric practices are beyond the reach of mere kings and queens. They are truly imperial. Like Ro- man emperors, they come, they see, and they con- quer. True, Roman emperors did substantially more than the “veni, vidi, vici” that they are credited with; they also died. But so do obstetric practices irrespective of whether or not the contemporary “plebs” bestow divinity upon them.

The above is, of course, entirely heretical when applied to something as heavenly and obviously beneficial as is electronic fetal monitoring. When obstetric litigation in a great country, like the United States, has rendered it “generally accepted that FHR monitoring is efficacious and capable of detecting asphyxia at an early enough stage to avoid neurologic damage,” (1) what more can one want? It must be outrageous to desire, let alone demand, that such great wisdom be reexamined in the light of something as common as a randomized controlled trial. Has experience, the very process that may engender hardening of the arteries and failing of the vision ( 2 ) , not taught us to respect the judgment of wise men and women?

When given a choice, what earthly reason can there be to substitute the evidence from a properly conducted randomized trial (3) for the wisdom and judgment of such men and women? After all, most randomized trials are not directly translatable to one’s own practice; if they were, we would have seen a mass of trials spring up all through the spe- cialty. On the other hand, who would doubt that courtroom obstetrics, to which Dr. Parer refered ( I ) , is perfectly translatable to all of our practices? A favorite of mine in that respect is a judgment pronounced, as long ago as 1983, by a West German high court of appeal. It stated that “every family doctor looking after a pregnancy must, by means of regular vaginal examinations, watch for signs that the fetus might die or has died already.” (4) Having performed countless vaginal examinations myself, I must admit that I have thus far failed to master the art of inducing the fetus to impart its state of health to my gloved fingers. Naturally, I don’t assume that this reflects my stupidity (I would be out of a job, if I did) and I certainly cannot blame the courtroom for it. So, it presumably reflects the ability of fetuses to recognize that my fingers are not those of a family doctor.