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Measuring biparietal diameter. The photograph shows James Willocks (left), who first introduced the fetal biparietal diameter as an indicator of gestational age and growth determined by ultrasound. He is using the early A-scanner, the Kelvin Hughes Mk IV Ultrasonic Flaw Detector. On the right, operated by an assistant, is a cephalometer, the prototype Electronic Calliper unit designed by T. C. Duggan. This measured precisely the time that the beam took to travel between the left and right sides of the head.
Photograph taken c.1963 in the Royal Materniy Hospital, Rottenrow, Glasgow.
British Medical Ultrasound Society.
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Constructing standards. Ultrasound is today the authoritative method for estimating gestational age and diagnosing abnormal development. But for it to achieve this status standard parameters and normal ranges first had to be determined. Donald’s team measured the distance between the left and right sides of the fetal head. This (‘biparietal’) parameter had already been used to estimate head size and predict pelvic disproportion, and was now recast as an indicator of fetal growth and development. Crown–rump length, first introduced by Franklin P. Mall in the early twentieth century, regained popularity as a means of dating early pregnancy. Sonography was compared with standards developed in other fields, such as Carnegie stages but mostly relied on the date of the last menstrual period in patients with regular cycles. With its wider adoption, large populations have been scanned to construct national and international standards, but it is still contested whether ethnic groups should have their own charts or differences should be explained by socio-economic factors.
Uses of ultrasound
Ultrasound was quickly accepted as a diagnostic tool, but the modes of use, frequency of examination and norms of safety and fetal development are still not fully standardized.
Between the 1950s and 1970s, physicians, physicists and engineers debated whether the scan should show a morphological image, akin to X-rays, or a graphical representation of deviations from the norm, like an electrocardiograph. In obstetrics the morphological orientation won, but different countries decided differently about frequency of use and indications for scanning, depending on whether ultrasound was framed as a diagnostic aid solely for pregnancies at risk, or a routine screening device for all.
Uses expanded beyond diagnosis. Around 1970, psychologists proposed that ultrasound could help the concerned mother ‘bond’ with the future child. Yet that bonding would have to be mediated, because at the time no untrained eye could interpret the scans. Professionals did this instead: obstetricians, midwives and specialized sonographers. Gradually, easier-to-read sonograms came to occupy a symbolic place in late twentieth-century popular culture. Many parents’ first visual encounter with their child was no longer at birth but seeing the gestational sac—a bright ring around a clear centre, characteristic of early pregnancy—or, even more powerfully, the embryonic heart beating on an ultrasound screen.
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‘Control of life’ in Life. The illustrated magazine Life played a key role in mid-twentieth-century American iconography. It pictured current events in dramatic, colourful images, with captions that often played on its title. Many Life images and especially covers gained iconic status. This picture of a woman lying next to an ultrasound machine was used to draw attention to a broader ongoing revolution, advertised in strikingly optimistic tones. But the woman’s face seems to convey anxiety; while we, the audience, perhaps watching from the doctor’s viewpoint, can see her baby’s head on the screen, she may not know how her pregnancy is proceeding.
Cover of Life magazine, vol. 59, no. 11, 10 September 1965. 35 x 27 cm.
Time & Life Pictures/Getty Images.
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‘Control of life’ in Life, 1965
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| Interpreting scans. How difficult these early ultrasound images were to interpret may be seen from this record card that includes a longitudinal ultrasound scan produced with the first contact scanner and originally recorded on 3000 ASA Polaroid film. It shows a normal 11-week fetus (‘cyesis’ means pregnancy). The fetal echoes are seen midway between the annotations ‘B’ (the patient’s full bladder) and ‘11 weeks’. The scan was performed by the research engineer John Fleming and either Donald, MacVicar or Helen Sawyers, a nurse who worked part-time on the ultrasound machine. The boxes below and to the left of the scan describe its type and position with respect to the abdominal midline.
Photograph taken in 1963 in ward D9/D10, Department of Gynæcology, Western Infirmary, Glasgow.
British Medical Ultrasound Society.
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Interpreting ultrasound scans, 1963
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