British Journal of Obstetrics und Gynaecology August 1976. V0183. pp 628-630


R. P. EDWARDS, Senior Registrar* AND

LINDACARDOZO, Senior House OJicer The Department of Obstetrics and Gynaecology Mill Road Maternity Hospital, Liverpool Summary Continuous recordings of maternal and fetal heart rate were made in 30 antenatal patients during simulated abdominal radiography in late pregnancy. Transient changes in fetal heart rate occurred in 43 per cent of patients in the supine position compared with 27 per cent in the prone position. Transient increases of maternal heart rate occurred in 37 per cent of patients. There was no evidence of revealed or concealed caval occlusion.

ALTERATION to the fetal heart rate may occur as a result of emotional change (Welford and Sontag, 1969; Hellman et al, 1961), sound (Sontag, 1962), vibrations (Grimwade et al, 1970 and 1971), sexual intercourse (Goodlin et al, 1972), and abdominal pressure (Walker et al, 1973). Abdominal X-rays in late pregnancy can be taken in the supine, prone or oblique positions. This study was undertaken to determine the possible effect on the maternal and fetal heart rates of radiological procedures carried out in late pregnancy.

METHODS The procedures described were performed on 30 volunteer patients from the antenatal ward of Mill Road Maternity Hospital, Liverpool. The reasons for antenatal hospital admission are listed in Table I. All patients were at more than 36 weeks gestation with a mean gestation of 37 - 4weeks. Seven patients were primigravidae and 23 were multiparous; the mean age was 25.6 years ranging from 16 to 43 years. Patients were excluded if the pregnancy was multiple, if


Present appointment: Consultant Obstetrician and Gynaecologist, Ormskirk and District General Hospital, Ormskirk, Lancashire.

polyhydramnios was present, if the fetus was thought to be growth retarded or if there was undue anxiety. The fetal heart rate was recorded continuously using a Sonicaid FM3 fetal monitor and an external electrode. The maternal heart rate was recorded continuously by electrocardiography using standard lead 11. Blood pressure was recorded at one minute intervals during each study. A standard X-ray table was used, and each patient was initially placed in the right lateral position for application of electrodes and to establish base line recordings. When a steady state was reached, the patient was moved to the supine position and an abdominal binder applied by a radiographer. After two minutes the binder was removed and the patient returned to the right lateral position until a steady base line state recurred. The patient was then placed in the prone position for two minutes and finally returned to the right lateral position. The time allowed to achieve a base line state was greater than five minutes in each case. All base line maternal heart rate and blood pressure recordings were within 5 beats per minute or 5 mm Hg of each other in each patient. Changes in maternal heart rate or fetal heart rate of more 628

HEART RATES AND RADIOGRAPHY TABLEI Reason for hospital admission

Table I1 also shows that the prone position resulted in fewer patients with alteration of fetal or maternal heart rates than the supine position with an abdominal binder. The changes which occurred were of the same magnitude except in one patient in whom the fetal heart rate fell rapidly to 75 beats per minute before returning to the base line level. This change was accompanied by an increase in the maternal heart rate of 25 beats per minute and the blood pressure rose from 120/80 to 150/95 mm Hg. Twenty-six patients (86 per cent) were more comfortable in the prone position than in the supine with added abdominal binder.

Number of patients Hypertension Pre-eclampsia Planned delivery Assessment of fetal maturity Ante-partum haemorrhage Unstable lie Removal of cervical suture Pyelonephritis


6 5

4 3 2 1 1



than 10 beats per minute, or alteration of systolic or diastolic blood pressure levels of more than 10 mm Hg were considered significant. Table I1 shows that significant changes in fetal heart rate occurred in 13 (43 per cent) of patients in the supine position with abdominal binders. In no patient was the change in fetal heart rate more than 25 beats per minute, nor the change in maternal heart rate more than 30 beats per minute. The systolic and diastolic pressures in one patient rose respectively by 20 mm Hg and 15 mm Hg; although this was associated with a rise in maternal heart rate, no alteration in fetal heart rate occurred.

RESULTS TABLEI1 Maternal and fetal heart rates in 30 patients examined in supine position with binder and also in prone position Supine position Prone with position binder

No change in fetal or maternal heart rate Fetal and maternal tachycardia Fetal tachycardia and maternal bradycardia Maternal tachycardia only Fetal tachycardia only Fetal bradycardia only


12 4

16 2

1 5 6 2

1 6 4 1

DISCUSSION Abdominal radiography in pregnancy may be carried out in the supine, prone or oblique positions. The application of abdominal binders reduces fetal motility and the amount of radiation the fetus receives. Change of fetal heart rate which may occur during abdominal radiographic procedures are most likely to be due to abdominal compression, caval occlusion or both. Walker et al (1973) showed that fetal heart rate deceleration is more common with compression of the head or neck whilst compression of thorax or trunk may produce acceleration. With a cephalic presentation the pressure effect of an abdominal binder or the prone position would act upon the fetal thorax or trunk and could explain fetal tachycardia whilst a bradycardia is more likely with a breech presentation. Two of the four patients with a breech presentation showed no change in fetal heart rate; a transient fetal tachycardia occurred in both prone and supine positions in one patient and a transient bradycardia in the prone position only in the remaining patient. The results show no evidence of concealed or revealed caval occlusion (Crawford, 1972). Transient maternal tachycardia is a normal response to the physical discomfort, or the emotional involvement, which inevitably must occur during these procedures. Although the majority of patients preferred the prone position there was no difference in the incidence of transient maternal tachycardia in either supine or prone position.



ACKNOWLEDGEMENTS We thank the Consultant Medical Staff of Mill Road Maternity Hospital for access to their patients, and Mrs B. Bentley, Senior Radiographer, Mill Road Maternity Hospital, for technical advice. REFERENCES Crawford, J. S. (1972) :Principles andpractice ofobstetric Anaesfhesia, 3rd edition. Blackwell Scientific Publications, London, p 16. Goodlin, R., Schmidt, W., and Creevy, D. (1972): Obstetrics and Gynecology, 39, 125.

Gnmwade, J., Walker, D., and Wood, C. (1970): Australian and New Zealand Journal of Obstetrics and Gynaecology, 10, 222. Grimwade, J., Walker, D., Bartlett, M., Gordon, S., and Wood, C. (1971): American Journal of Obstetrics and Gynecology, 109, 86. Hellman, L. M., Johnson, H. L., Tolles, W. E., and Jones, E. H. (1961): American Journal of Obstetrics and Gynecology, 82. 1055. Sontag, L. W. (1962): Psychosomatic Obstetrics, Gynaecology and Endocrinology. Edited by W. S. Kroger. C . C. Thomas, Springfield, p 9. Walker, D., Grimwade, J., and Wood, C. (1973): Obstetrics and Gynecology, 41, 351. Welford. N. T., and Sontag, L. W. (1969): American Journal of Psychology, 34, 276.

Changes in fetal and maternal heart rate during abdominal radiography in late pregnancy.

British Journal of Obstetrics und Gynaecology August 1976. V0183. pp 628-630 CHANGES IN FETAL AND MATERNAL HEART RATE DURING ABDOMINAL RADIOGRAPHY IN...
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