BRITISH MEDICAL JOURNAL
707
12 MARCH 1977
trained, cheaper staff. This is shown clearly in the figures which relate to their members in training. Between 1967 and 1973 the number of pupil (State enrolled) nurses in England and Wales increased by 34",,, whereas the number of student (State registered) nurses decreased by 4", It may be right that the trend in nursing to shift away from more highly specialised staff is correct, but can we accept this when doctors show no signs of endorsing a similar shift by the introduction of a feldscher or "physician's assistant ?" The training cost of a doctor was said to be C40 000, in reply to a parliamentary question in August 1976 (not f30 000 as stated in your article). If, as seems probable, the cost of training and employing the doctors is at the expense of the quality of nursing staff-how common are the complaints about the lack of trained staff at night-or, even worse, a cause of a future decrease in the nurse to doctor ratio, then the medical manpower policy will have failed, whatever the number of doctors
produced. MUIR GRAY Oxford British Medical 7ournal, 1976, 1, 594. 2 British Medical 7ournal, 1976, 2, 377.
SIR,-Your conversion to the cause of the rational manpower planning of medical staff (leading article, 19 February, p 465), though somewhat belated, must be welcomed. As the proposer of the rider at last year's annual representative meeting (7 August 1976, p 380) recommending that medical school intake should be at a level appropriate for service and traning needs, I have consistently argued for sound monitoring and planning of future manpower requirements. I feel, however, that you are unfair in placing the burden of inflexibility on the universities and the Department of Health and Social Security. I have found that very few doctors, when faced with rational forecasts of future medical manpower, have the courage or foresight to make the inevitable projections from these forecasts. Indeed, it was the then chairman of Council who spoke against the rider, feeling that it was untimely and that, for that reason, a policy decision should be delayed. I regard it as highly significant that, within a space of six months, the Association has moved to a position where review and monitoring of manpower needs have become matters too urgent to wait for the final report of the Royal Commission. I feel that this issue is of the utmost importance, particularly regarding the aspirations of the extremely competent young people now entering our medical schools; we have a duty to ensure that every doctor is appraised of the facts so that, as a profession, our attitude is soundly based on practicalities and not
prejudice. J M CUNDY Lewisham Hospital, London SE13
Induction of labour and perinatal
mortality SIR,-Dr Margaret B McNay and her colleagues (5 February, p 347) conclude that their "results suggested that increased use of induction of labour has contributed to an improved perinatal mortality rate." Unfortunately their data provide little support for
that conclusion. Plotting their annual induction and perinatal mortality rates together with Scottish perinatal mortality data shows a much less clear relationship than they suggest (see figure). Firstly, there is a general falling tendency in perinatal mortality rates for most parts of the country (clearly shown in data for Scotland as a whole given in the Annual Reports of the Registrar General). Comparison of most fiveyear periods with the previous five years would almost inevitably reveal a "significant fall." Secondly, the Glasgow data actually show a less convincing fall in perinatal mortality than is generally found. The increase in induction seems to have been associated in Glasgow with an interruption in the generally downward trend in the earlier years. In 1970, 1971, and 1972 the perinatal mortality rate was higher than in 1969 and in 1975 the rate was again as high as in 1969. Thirdly, the crucial comparison-that of perinatal mortality in induced and noninduced labour-is not made in their data. There are many problems in the interpretation of such a comparison, but without it we are in a poor position to draw any conclusions at all. The appraisal of clinical innovation is far from easy and we are reluctant to make comments which may deter future investigations in this field. However, induction of labour is important both for its greatly increased use and for the many controversies already surrounding it. Its appraisal demands the most rigorous standards of epidemiological and clinical interpretation and probably much more subtle criteria than the perinatal death rate, whose uncertain trends, particularly in small volumes of data, are very difficult to interpret.
JOYCE LEESON ALWYN SMITH Department of Community Health, University of Manchester
SIR,-Dr Margaret B McNay and her colleagues (5 February, p 347) refer to the difficulty of drawing conclusions about the benefits of induced labour because of the way previously published work has been analysed. These difficulties persist and have already been adequately acknowledged by others,t-3 but Dr McNay and her colleagues are obviously 34 33 32 31
(1) Their table IV shows that over half the fall in the "mature, unknown" death rate is due to a reduction of deaths during labour and the neonatal period. It seems plausible that obstetric and paediatric influences other than induction may have contributed to this fall. (2) The authors have previously published their opinion that elective induction of labour at term might improve perinatal mortality.6 The study on which they based these views compared a 46 % with a 90 °t) induction rate. We are therefore surprised that Dr McNay and her colleagues fail to comment either on the failure of the "mature, unknown" death rate to improve as the induction rate rose from 31 7 to 40 6 (between 1970 and 1974) or on the fact that there was no deterioration in the death rate as the induction rate fell (between 1974 and 1975). (3) We are puzzled by the example of "lives saved" in their discussion. Our calculations, using the rates given in their paper, give a different number of "expected deaths" suggesting that they have overestimated the number of "lives saved" by 20 ", .
Perinatal
mortality
-
-
under the impression that they have cut the Gordian knot. Their study documents trends in perinatal mortality and induction of labour in cases selected for hospital delivery. However, 16 4"O of Glasgow women were delivered outside hospital in 19664 compared with almost universal hospital confinement at the end of their study period. The referral pattern to the various Glasgow maternity units may also have been altering during this time. We can illustrate the magnitude of the bias which can result from ignoring these considerations. Our own study of trends in obstetric management and outcome of pregnancy in Cardiff residents between 1965 and 1973 used a geographically defined population.} Over the nine years studied the pooled perinatal mortality rate was 26 0 per 1000 and the annual decline was 0-22 per 1000 per year. Had our study population consisted of hospital deliveries the pooled perinatal mortality rate would have been 29-7 per 1000 and the annual decline 1 23 per 1000 per year. We would thus have made a considerable overestimate of the true fall in perinatal mortality. Similarly, we would have underestimated the real increase in induction and caesarean section rates. Satisfactory interpretation of the data used by Dr McNay and her colleagues is difficult in view of the uncertainties surrounding the selection of their study population. Nevertheless,there are some further points we would like to make:
Induction rate
\ ( McNay eVol table II)
(McNay et a/
30129
table I)
,/
39 37 35
28Relation of induction
rate 1966-75 at Glasgow Royal Maternity Hospital and associated hospitals to perinatal mortality at those hospitals and in Scotland as awhole.
27
~ 2 *- 26 -
Perinatal'',
mortalIi ty
)2 5 (Scotland*,
"
x
~
-
/
.. x
3 A 29 o
-X
E 24 _ 23 a
\
/'
/27
x27 25
a 22 21 cX 20
231
19
\
_ --
8 17
21919
/
-\
17
15
TJ
r 966
67
68
72 73 74 75 69 70 71 *AnnuOl Reports of RCgistrar General Scot/and
707
12 MARCH 1977
trained, cheaper staff. This is shown clearly in the figures which relate to their members in training. Between 1967 and 1973 the number of pupil (State enrolled) nurses in England and Wales increased by 34",,, whereas the number of student (State registered) nurses decreased by 4", It may be right that the trend in nursing to shift away from more highly specialised staff is correct, but can we accept this when doctors show no signs of endorsing a similar shift by the introduction of a feldscher or "physician's assistant ?" The training cost of a doctor was said to be C40 000, in reply to a parliamentary question in August 1976 (not f30 000 as stated in your article). If, as seems probable, the cost of training and employing the doctors is at the expense of the quality of nursing staff-how common are the complaints about the lack of trained staff at night-or, even worse, a cause of a future decrease in the nurse to doctor ratio, then the medical manpower policy will have failed, whatever the number of doctors
produced. MUIR GRAY Oxford British Medical 7ournal, 1976, 1, 594. 2 British Medical 7ournal, 1976, 2, 377.
SIR,-Your conversion to the cause of the rational manpower planning of medical staff (leading article, 19 February, p 465), though somewhat belated, must be welcomed. As the proposer of the rider at last year's annual representative meeting (7 August 1976, p 380) recommending that medical school intake should be at a level appropriate for service and traning needs, I have consistently argued for sound monitoring and planning of future manpower requirements. I feel, however, that you are unfair in placing the burden of inflexibility on the universities and the Department of Health and Social Security. I have found that very few doctors, when faced with rational forecasts of future medical manpower, have the courage or foresight to make the inevitable projections from these forecasts. Indeed, it was the then chairman of Council who spoke against the rider, feeling that it was untimely and that, for that reason, a policy decision should be delayed. I regard it as highly significant that, within a space of six months, the Association has moved to a position where review and monitoring of manpower needs have become matters too urgent to wait for the final report of the Royal Commission. I feel that this issue is of the utmost importance, particularly regarding the aspirations of the extremely competent young people now entering our medical schools; we have a duty to ensure that every doctor is appraised of the facts so that, as a profession, our attitude is soundly based on practicalities and not
prejudice. J M CUNDY Lewisham Hospital, London SE13
Induction of labour and perinatal
mortality SIR,-Dr Margaret B McNay and her colleagues (5 February, p 347) conclude that their "results suggested that increased use of induction of labour has contributed to an improved perinatal mortality rate." Unfortunately their data provide little support for
that conclusion. Plotting their annual induction and perinatal mortality rates together with Scottish perinatal mortality data shows a much less clear relationship than they suggest (see figure). Firstly, there is a general falling tendency in perinatal mortality rates for most parts of the country (clearly shown in data for Scotland as a whole given in the Annual Reports of the Registrar General). Comparison of most fiveyear periods with the previous five years would almost inevitably reveal a "significant fall." Secondly, the Glasgow data actually show a less convincing fall in perinatal mortality than is generally found. The increase in induction seems to have been associated in Glasgow with an interruption in the generally downward trend in the earlier years. In 1970, 1971, and 1972 the perinatal mortality rate was higher than in 1969 and in 1975 the rate was again as high as in 1969. Thirdly, the crucial comparison-that of perinatal mortality in induced and noninduced labour-is not made in their data. There are many problems in the interpretation of such a comparison, but without it we are in a poor position to draw any conclusions at all. The appraisal of clinical innovation is far from easy and we are reluctant to make comments which may deter future investigations in this field. However, induction of labour is important both for its greatly increased use and for the many controversies already surrounding it. Its appraisal demands the most rigorous standards of epidemiological and clinical interpretation and probably much more subtle criteria than the perinatal death rate, whose uncertain trends, particularly in small volumes of data, are very difficult to interpret.
JOYCE LEESON ALWYN SMITH Department of Community Health, University of Manchester
SIR,-Dr Margaret B McNay and her colleagues (5 February, p 347) refer to the difficulty of drawing conclusions about the benefits of induced labour because of the way previously published work has been analysed. These difficulties persist and have already been adequately acknowledged by others,t-3 but Dr McNay and her colleagues are obviously 34 33 32 31
(1) Their table IV shows that over half the fall in the "mature, unknown" death rate is due to a reduction of deaths during labour and the neonatal period. It seems plausible that obstetric and paediatric influences other than induction may have contributed to this fall. (2) The authors have previously published their opinion that elective induction of labour at term might improve perinatal mortality.6 The study on which they based these views compared a 46 % with a 90 °t) induction rate. We are therefore surprised that Dr McNay and her colleagues fail to comment either on the failure of the "mature, unknown" death rate to improve as the induction rate rose from 31 7 to 40 6 (between 1970 and 1974) or on the fact that there was no deterioration in the death rate as the induction rate fell (between 1974 and 1975). (3) We are puzzled by the example of "lives saved" in their discussion. Our calculations, using the rates given in their paper, give a different number of "expected deaths" suggesting that they have overestimated the number of "lives saved" by 20 ", .
Perinatal
mortality
-
-
under the impression that they have cut the Gordian knot. Their study documents trends in perinatal mortality and induction of labour in cases selected for hospital delivery. However, 16 4"O of Glasgow women were delivered outside hospital in 19664 compared with almost universal hospital confinement at the end of their study period. The referral pattern to the various Glasgow maternity units may also have been altering during this time. We can illustrate the magnitude of the bias which can result from ignoring these considerations. Our own study of trends in obstetric management and outcome of pregnancy in Cardiff residents between 1965 and 1973 used a geographically defined population.} Over the nine years studied the pooled perinatal mortality rate was 26 0 per 1000 and the annual decline was 0-22 per 1000 per year. Had our study population consisted of hospital deliveries the pooled perinatal mortality rate would have been 29-7 per 1000 and the annual decline 1 23 per 1000 per year. We would thus have made a considerable overestimate of the true fall in perinatal mortality. Similarly, we would have underestimated the real increase in induction and caesarean section rates. Satisfactory interpretation of the data used by Dr McNay and her colleagues is difficult in view of the uncertainties surrounding the selection of their study population. Nevertheless,there are some further points we would like to make:
Induction rate
\ ( McNay eVol table II)
(McNay et a/
30129
table I)
,/
39 37 35
28Relation of induction
rate 1966-75 at Glasgow Royal Maternity Hospital and associated hospitals to perinatal mortality at those hospitals and in Scotland as awhole.
27
~ 2 *- 26 -
Perinatal'',
mortalIi ty
)2 5 (Scotland*,
"
x
~
-
/
.. x
3 A 29 o
-X
E 24 _ 23 a
\
/'
/27
x27 25
a 22 21 cX 20
231
19
\
_ --
8 17
21919
/
-\
17
15
TJ
r 966
67
68
72 73 74 75 69 70 71 *AnnuOl Reports of RCgistrar General Scot/and
