AMNIOCENTESES AND THE ALPHA-FETOPROTEIN SCREENING PROGRAMME

39 the hyperalgesia on the scalp I suggest that the virus and the reaction to it spread from the glossopharyngeal nerve ganglion into the trigeminal nerve nucleus. Moreover, the two cases indicate clinical evidence of glossopharyngeal nerve involvement in the overlapping innervation on the scalp in man. To

explain

zoster

I thank Dr P. W. Nathan for advice, Dr F. Robertson and Prof. F. W. L. Kerr for their help, and Mrs S. Vernon who typed the manu-

script. 54 Cockton Hill

Road,

Bishop Auckland, County Durham DL14

6HS

J. CLARK

AMNIOCENTESES AND THE ALPHA-FETOPROTEIN SCREENING PROGRAMME a national programme for the neural-tube defects by screening of detection of open prenatal alpha-fetoprotein (A.F.P.) in maternal serum it is important that the causes of fetal loss after amniocentesis in pregnancies with raised serum-A.F.p. levels are understood. The uninformed reader of Mr Bennett’s letter (Nov. 4, p. 987) might well be disturbed to learn that there was a 10-7% loss-rate of apparently normal fetuses after amniocentesis. Bennett misleads when he compares this rate unfavourably with studies’2 in which the indications for amniocentesis were different, and when he states that the 21 terminated pregnancies with spina bifida must be seen against the 16 unaffected pregnancies lost. He apparently fails to appreciate the evidence that the cause of the increased fetal loss-rate is directly related to the cause of the raised serum-A.F.p. and is not due simply to the complications of amniocentesis. Out of 17 707 pregnancies tested in the West of Scotland study3 only 101 (0.6%) proceeded to amniocentesis. 51 of these pregnancies had a raised amniotic A.F.P. due to fetal abnormality and were terminated. In the 50 continuing pregnancies 8 (16%) were lost by abortion (4) or perinatal death (4). 6 of the 8 losses were in pregnancies which had threatened to abort before amniocentesis; the other was in a twin pregnancy with fetus papyra us which aborted at 26 weeks. This rate of fetal loss was to be expected since fetomaternal hxmorrhage in threatened abortion is a well-recognised cause of raised serum-A.F.p. Maternal serum-A.F.p. screening programmes thus identify pregnancies destined either to miscarry or be associated with fetal complications later. If such pregnancies have amniocentesis it is obvious that the fetal loss-rate will be higher than in pregnancies tested for other indications. ’ Our experience suggests a simple working hypothesis which could account for many of the unexplained false-positive serum-A.F.p. results and for the association of raised serum-A.F.p.

SIR,—In discussions about

1. N.I.C.H.H.D.

Registry for Amniocentesis Study Group. J. Am. med. Ass. 1976, 236, 1471. 2. Simpson, N. E., Dallaire, L., Miller, J. R., Siminovich, L., Hamerton, J. C., Miller, J , McKeen, C. Can. med. Ass. J. 1976, 115, 739. 3. Ferguson-Smith, M. A., Rawhnson, H. A., May, H. M., Tait, H. A., Vince, J. D, Gibson, A. A. M., Robinson, H. P., Ratdiffe, J. G. Lancet, 1978, i, 1330.

levels with low

initial

event

might

be

a

circulation. If this was associated with overt vaginal bleeding, the event would be recognised as a threatened abortion; if not, the event could be considered a "concealed" threatened abortion recognisable only by ultrasonic evidence of a retroplacental clot or by evidence of placental abnormality at delivery. If threatened abortion is suspected, a second serum-A.F.p. test may be helpful in determining the need for amniocentesis because the A.F.P. level invariably drops to normal in patients who have recovered from the episode. In our view it would be important to develop reliable methods for recognising concealed threatened abortion in which fetomaternal hemorrhage continues, so that the patient may be spared the necessity of amniocentesis. Evidence in favour of our explanation of fetal loss and falsepositive results in serum-A.F.p. screening programmes may be obtained by looking more closely at the results presented in Bennett’s letter. The table shows the data on fetal loss after amniocentesis from four centres in the U.K., each of which operates a different screening policy which influences the proportion of patients requiring amniocentesis. The centre with the lowest amniocentesis-rate has the highest fetal loss-rate among those proceeding to amniocentesis, and vice versa. However, when the fetal loss-rate is considered in terms of the number of patients screened, the rate is lowest in the centre with the highest loss after amniocentesis. In particular, the fetal loss-rates in total pregnancies screened are almost identical in the Edinburgh and West of Scotland series, despite the fact that the loss after amniocentesis is 5 -5 times higher in the West of Scotland. This can be interpreted on the basis that each series contains a similar proportion of apparent or concealed threatened abortions with raised maternal serum-A.F.p. levels which are destined to end in fetal loss later on. Further evidence that the fetal loss-rate reported in serum screening programmes is unrelated to the hazards of amniocentesis can be drawn from a previous study by Bennett et al.5 9 of 99 singleton pregnancies with high maternal serum-A.F.p. levels were lost by abortion (5), stillbirth (1), or neonatal death (3), although only 30 of the patients had amniocentesis. Although we are not told which of these losses occurred in the patients who had amniocentesis, the overall fetal loss-rate was thus similar to the 8.3% loss subsequently found by the Oxford group (see Bennett’s letter) among a series of patients all of whom were submitted to amniocentesis. We believe that voluntary serum-A.F.p. screening is a humane and effective procedure for the reduction of open neuraltube defect births and would not wish to see the establishment of a national programme delayed by misleading and unsub-

4.

Brock, D. J. H., Barron, L., Jelen, P., Watt, M., Scrimgeour, J. B. ibid. 1977, ii, 267. 5. Wald, N., Cuckle, H., Stirrat, G. M., Bennett, M. J., Turnbull, A. C. ibid. 1977, ii, 268. 6 Brock, D. J. H., Scrimgeour, J. B., Steven, J., Barron, C., Watt, M. Br. J. Obstet. Gynœc. 1978, 85, 575. 7. Gosden, C., Brock, D. J. H. Br. med. J. 1978, ii, 1186

FETAL LOSS AFTER AMNIOCENTESES

*Bennett’s letter of Nov. 4.

birth-xveight.1The

placental lesion, leading to fetal haemorrhage into the maternal

40

claiming a high rate of fetal loss among normal pregnancies due to the screening process.

stantiated reports

Departments of Medical Genetics, and Pathology, Royal Hospital for Sick Children, Glasgow G3 8SJ

M. A. FERGUSON-SMITH A. A. M. GIBSON

Department of Midwifery, Yorkhill and Associated Hospitals,

Glasgow

C. R. WHITFIELD

Radioimmunoassay Unit, Biochemistry Department, Royal Infirmary, Glasgow

J. G. RATCLIFFE

SIR,-The U.K. Collaborative Study’ stated that over 90% of infants with neural-tube defects are born to women who have not previously had affected children. This is being misinterpreted-for example, by Dr Chamberlain (Dec. 16, p. 1293)-as "some 10% of these [N.T.D.] births would have occurred in previously affected families who would be offered amniocentesis in the absence of a serum screening pro-

gramme". The proportion of index patients who, in large series, had a previously affected sib was for a very high incidence area 6%2 and in a low-incidence area 4%.3 It is better, therefore, to take 5% rather than 10% as the proportion of cases of spina bifida and anencephaly who will have had a previously affected sib. M.R.C. Clinical Genetics Unit, Institute of Child Health, London WC1N 1EH

cited out of context from our paper on maternal serand spontaneous abortion.’ He did so for the first time in his letter of Nov. 4 and although we pointed out the error in your correspondence columns of Nov. 18 he has not corrected it. Contrary to Mr Bennett’s statements, in both his letter and article, we demonstrated that women with a high serum-A.F.p. level were more likely to have a spontaneous abortion than were women with normal A.F.P. levels.

again

um-A.F.p.

I.C.R.F. Cancer Epidemiology and Clinical Trials Unit, Department of Regius Professor of Medicine, Radcliffe Infirmary, Oxford OX2 6HE

NICHOLAS WALD SHEILA BARKER HOWARD CUCKLE

Department of Human Genetics, Western General Hospital,

Edinburgh

DAVID BROCK

Nuffield Department of Obstetrics and Gynæcology, John Radcliffe Hospital, Oxford

GORDON STIRRAT

EDUCATING DEAF CHILDREN IN ORDINARY SCHOOLS

SIR,—In the light of Dr Dale’s paper5 your readers might be interested in a system which specialises in educating deaf and partially hearing children individually in ordinary schools in Scotland. Since 1961 professional oversight has been available from the Gateside Centre in Paisley, offering to heads of schools, classroom teachers, and parents a peripatetic service of information and support by which profoundly deaf children receive their education in ordinary schools. Individual programmes in speech and linguistic skills are planned for each child and daily tuition is given in the hearing school by trained teachers of the deaf. These lessons, of an hour’s duration, are supplemented 1. U.K. Collaborative

Study

There

on

Alpha-fetoprotein

Defects. Lancet, 1977, i, 1323. 2. Carter, C. O., David, P. A., Lawrence, K. M. 3. Carter, C. O., Evans, K. ibid. 1973,10, 209. 4. Wald, N., Barker, S., Cuckle, H., Brock, D. Obstet. Gynœc. 1977, 84, 357. 5. Dale, D. M. C. Lancet, 1978, ii, 884.

in

J.

Relation

to

Neural Tube

med. Genet. 1968,

5, 81.

115 children in

our

programme, 37 of whom have

deafness. All decisions on the child’s management and future education are taken by a panel consisting of the principal psychologist, the senior clinical medical officer, the otolaryngologist, and the head teacher of the school for the deaf, in consultation with the parents and others (e.g., child psychiatrists, paediatricians, and social workers). At the Gateside Centre there is a parent guidance programme, a diagnostic unit, and a pre-school nursery. Parents’ workshops are held regularly in the evenings. Courses in hearing schools, for teachers, who have deaf children in their classes, take place during term time. Of the pupils who have left our educational establishment over the past five years 2 have university degrees, and 10 attended further education colleges passing examinations in subjects ranging from business studies through mathematics to English and catering. Some students passed these subjects at 0 or A level standard. The remainder completed their secondary school courses and have since, despite their hearing loss, gained employment suitable to their age, aptitude, and ability". As far as we know no former pupil is unemployed. Argyll & Clyde Health Board, Paisley PA1 1DU

J. MORAG MACARTHUR

Gateside Centre for the Deaf

M. BURTON

SCREENING AND CERVICAL CANCER

SIR,—Macgregor and Teper’ should not really state that screening for cervical cancer has been done "particularly so" in Scotland and then not explain why the impact on mortality "differs remarkably little between England and Wales, and Scotland". A difference of 2 or 3 cases in the Tayside and Grampian figures could have reversed Macgregor and Teper’s conclusions,2 and in any case it was pointed out in 19663 that mortality had been falling in England and Wales ever since 1948-long before screening was introduced. Screening has been much more intensive in British Columbia than in more populous Ontario and Quebec4 or in New Zealand,5 and more intensive in New Zealand (since 1954) than in England and Wales or in Scotland. Nevertheless, the incidence of cervical cancer in British Columbia for 1969-71 was greater than that in Ontario and Quebec4 or in New Zealand;5 and New Zealand incidence and mortality figures are no better than those for England and Wales and Scotland cited by Macgregor and Teper. A greater question mark against the validity of the claims made for screening lies in the increasing mortality now being seen in women of 20-34, the most heavily screened group, in England and Wales and in New Zealand.5It is not sufficient to refer vaguely to cervical cancer as a parallel to venereal disease, or to imply that there is plenty of time after an atypical smear before "microinvasion" is reached, as Macgregor and Teper have done. Until this discrepancy has been properly explained their claims for the benefits of screening must be regarded with some scepticism. Postgraduate School of Obstetrics and Gynæcology University of Auckland, National Women’s Hospital, Auckland 3, New Zealand

G. H. GREEN

SIR The argument on screening techniques is polarising between those who passionately believe in it as a fundamental of preventive medicine and those who think that the money could be spent in other areas of patient care. We do not see this 1.

Macgregor, E., Teper, S. Lancet, 1978, ii, 774. Crombie, I. K. ibid. p. 1084. 3. Hammond, E. C., Siedman, H. Archs envir. Hlth, 1966, 13, 105. 4. Walton Report Can. med. Ass. J. 1976, 114, 1003. 5. Green, G. H. Br. J. Obstet. Gynœc. (in the press).

2.

J. H., Stirrat, G. M. Br. J.

are

profound hearing impairment. All deaf children go into ordinary school at five years of age irrespective of the degree of

C. O. CARTER K. A. EVANS

SIR,—MR Bennett, in his joint article (Dec. 16, p. 1296), has

by visits to parents.