To bookmark:

Login or Sign Up

Ultrasound In Pregnancy

By Pathways Magazine

Ultrasound: high-frequency sound waves that travel at 10 to 20 million cycles per second. The pattern of echo waves creates a picture of tissue and bone.

In 1987, UK radiologist H.D. Meire, who had been performing pregnancy scans for 20 years, commented, “The casual observer might be forgiven for wondering why the medical profession is now involved in the wholesale examination of pregnant patients with machines emanating vastly different powers of energy which is not proven to be harmless to obtain information which is not proven to be of any clinical value by operators who are not certified as competent to perform the operations”.

Routine prenatal ultrasound (RPU) actually detects only between 17 and 85 percent of the 1 in 50 babies who have major abnormalities at birth. RPU can identify a low-lying placenta (placenta previa). However, 19 of 20 women who have placenta previa detected on an early scan will be needlessly worried: the placenta will effectively move up without causing problems at the birth. Furthermore, detection of placenta previa by RPU has not been found to be safer than detection in labor.

The American College of Obstetricians has concluded that “in a population of women with low-risk pregnancies, neither a reduction in perinatal morbidity and mortality nor a lower rate of unnecessary interventions can be expected from routine diagnostic ultrasound. Thus ultrasound should be performed for specific indications in low-risk pregnancy.

Effects of ultrasound include cavitation, a process wherein the small pockets of gas that exist within mammalian tissue vibrate and then collapse. In this situation ‚Äú…temperatures of many thousands of degrees Celsius in the gas create a wide range of chemical products, some of which are potentially toxic. These violent processes may be produced by microsecond pulses of the kind which are used in medical diagnosis.‚Äù (American Institute of Ultrasound Medicine Bioeffects Report 1988). The significance of cavitation in human tissue is unknown.

Studies have suggested that these effects are of real concern in living tissues:

  • Cell abnormalities caused by exposure to ultrasound were seen to persist for several generations.
  • In newborn rats (similar stage of development as human fetuses at four to five months in utero), ultrasound can damage the myelin that covers nerves.
  • Exposing mice to dosages typical of obstetric ultrasound cased a 22% reduction in the rate of cell division and doubling of the rate of aptosis (programmed cell death), in the cells of the small intestine.
  • Two long-term randomized controlled trials comparing exposed and unexposed childrens‚Äô development at eight to nine years old found no measurable effect from ultrasound. However, the authors comment that intensities used today are many times higher than there were in 1979 and 1981.

РExcerpted from “Ultrasound Scans: Cause for Concern”


  • American College of Obstetricians and Gynecologists (ACOG) Routine Ultrasound in Low-Risk Pregnancy. In:ACOG Practice Patterns- Evidence-Based Guidelines for Clinical Issues in Obstetrics and Gynecology. Number 5 August 1997
  • Association for Improvements in the Maternity services (AIMS)- AIMS UK. Ultrasound Unsound? AIMS Journal vol 5 no 1, spring 1993. The updated version is available from:
  • American Institute of Ultrasound Medicine Bioeffects Report 1988. J Ultrasound Medicine 7S1-S38. Sept 1988
  • Beech BL. Ultrasound- unsound? Talk at Mercy Hospital, Melbourne, April 1993
  • Brand IR, Kaminopetros P, Cave M et al. Specificity of antenatal ultrasound in the Yorkshire region: a prospective study of 2261 ultrasound detected anomalies. Br J Obstet Gynaecol 1994. Vol 101, no5. pp 392-397
  • Brookes, A. Women’s experience of routine prenatal ultrasound. Healthsharing Women: The newsletter of Healthsharing Women’s Health Resource Service. Vol 5, no’s 3 & 4. Dec 1994- March 1995. Campbell JD et al Case-control study of prenatal ultrasonography in children with delayed speech. Can Med Ass J 1993 vol 149 no 10 pp1435-1440
  • Chan FY. Limitations of Ultrasound. Paper presented at Perinatal Society of Australia and New Zealand 1st Annual Congress, Freemantle 1997
  • Davies J et al. Randomised controlled trial of doppler ultrasound screening of placental perfusion in pregnancy. Lancet 1992;340:1299-1303
  • De Crespigny L, Dredge R. Which Tests for my Unborn Baby, Revised Edition. Oxford University Press, Melbourne 1996.
  • Ellisman MH, Palmer DE, Andre MP. Diagnostic levels of ultrasound may disrupt myelination. Experimental Neurology 1987 vol 98 no 1 pp78-92
  • Ewigman BG, Crane JP, Frigoletto FD et al. Effect of prenatal ultrasound screening on perinatal outcome.RADIUS study group. N Engl J Med . 1993 vol 329, no 12, pp821-7
  • Geerts JGM, Brand E, Theron B. Routine obstetric ultrasound in South Africa: cost and effect on perinatal outcome- a prospective randomised controlled trial. Br J Obstet Gynaecol 1996. Vol 103. pp501-507
  • Kieler H, Axelsson O, Nilsson S, Waldenstrom U. Comparison of ultrasonic measurement of biparietal diameter and last menstrual period as a predictor of day of delivery in women with regular 28 day cycles. Acta-Obstet-Gynecol-Scand, 1993 vol 75 no 5 pp 347-9 Kieler H, Axelsson O, Haguland B, et al. Routine ultrasound screening in pregnancy and the children’s subsequent handedness. Early Hum Dev 1998 , vol 50 no 2, pp233-245
  • Kieler H, Ahlsten G, Haguland B et al. Routine ultrasound screening in pregnancy and the children’s subsequent neorological development. Obstet Gynecol 1998 vol 91 5 (pt 1) pp750-6 Kieler H, Cnattingius S, Haglund B et al. Sinistrality- a side-effect of prenatal sonography: A comparative study of young men.Epidemiology 2001:12 (6):618-23
  • Luck CA. Value of routine ultrasound scanning at 19 weeks: a four year study of 8849 deliveries. BMJ 1992, vol 34, no 6840, pp1474-8
  • Liebeskind D, Bases R, Elequin F et al. Diagnostic ultrasound: effects on the DNA and growth patterns of animal cells. Radiology 1979 vol 131, no1, pp 177-184
  • Lorenz RP, Comstock CH, Bottoms SF, Marx SR. Randomised prospective trial comparing ultrasonography and pelvic examination for preterm labor surveillance. Am J Obstet Gynecol 1990 vol 162 no 6 pp 1603-1610
  • Marinac-Dabic D, Krulewitch CJ, Moore RM Jr. The safety of prenatal ultrasound exposure in human studies. Epidemiology 2002 May; 13(3 Suppl):S19-22
  • Meire HB. The safety of diagnostic ultrasound (commentary). Br J Obstet Gynaecol 1987 vol 94, pp1121-1122
  • MIDIRS. Informed Choice for professionals leaflet no 3. Ultrasound screening in the first half of pregnancy: is it useful for everyone? MIDIRS and the NHS centre for Reviews and Dissemination. 1996
  • Mole R. Possible hazards of imaging and Doppler ultrasound in obstetrics. Birth 1986 vol 13, pp329-37
  • Neilson JP.Ultrasound for fetal assessment in early pregnancy (Cochrane Review). In:The Cochrane Library, Issue 2, 2002. Oxford” Update Software
  • New Scientist Shadow of doubt 12 June 1999, p23 Newnham J, Evans SF, Michael CA et al. Effects of frequent ultrasound during pregnancy: a randomised controlled trial. Lancet 1993, vol 342, no 8876, pp887-91
  • Newnham JP et al. Doppler flow velocity wave form analysis in high risk pregnancies: a randomised controlled trial. Br J Obstet Gynaecol, 1991,vol 98 no 10, pp956-963
  • Oakley Ann The history of ultrasonography in obstetrics. Birth, 1986 vol 13, no 1, pp 8-13
  • Odent M. Where does handedness come from? Primal Health Research Quarterly 1998, vol 6 no 1.
  • Olsen O et al. Routine ultrasound dating has not been shown to be more accurate than the calendar method. Br J Obstet Gynaecol 1997, Vol 104 No 11 pp1221-2
  • Rothman, Barbara Katz. The Tentative Pregnancy: Amniocentesis and the Sexual Politics of Motherhood. (2nd ed) Pandora 1994 Saari-Kemppainen A, Karjalainen O, Ylostalo P et al. Ultrasound screening and perinatal mortality: controlled trial of systematic one-stage screening in pregnancy. The Helsinki ultrasound trial. Lancet 1990 vol 336, no 8712. pp 387-391
  • Salvesen KA, Bakketeig LS, Eik-nes SH et al. Routine ultrasonography in utero and school performance at age 8-9 years. Lancet 1992, vol 339 no 8785 pp 85-89
  • Salvesen KA, Vatten LJ, Eik-nes SH et al. Routine ultrasonography in utero and subsequent handedness and neurological development. BMJ 1993: vol 307 no 6897 pp159-64
  • Salvesen KA, Ein-nes SH et al. Ultrasound during pregnancy and subsequent childhood non-right handedness- a meta-analysis. Ultrasound Obstet Gynecol 1999; 13(4) 241-6.
  • Sparling JW, Seeds JW, Farran DC. The relationship of obstetric ultrasound to parent and infant behavior. Obstet Gynecol 1988 vol 72 no 6. pp 902-7
  • Senate Community Affairs Reference Committee. Rocking the Cradle- A Report into Childbirth Procedures. Commonwealth of Australia 1999
  • Stark CR, Orleans M, Havercamp AD et al. Short and long term risks after exposure to diagnostic ultrasound in utero. Obstet Gynecol, 1984, vol 63 pp 194-200
  • Taylor KJW A prudent approach to ultrasound imaging of the fetus and newborn. Birth 1990. Vol 17 no 4, pp218-223
  • Testart J, Thebalt A, Souderis E, Frydman R. Premature ovulation after ovarian ultrasonography. Br J Obstet Gynaecol, 1982, vol 89, no 9, pp 694-700
  • Thacker SB. Quality of controlled clinical trials. The case of imaging ultrasound in obstetrics: a review. Br J Obstet Gynaecol, 1985 vol 92, no 5, pp 437-444
  • Wagner M. Ultrasound; More harm than good? Mothering magazine Winter 1995
  • Watkins D. An alternative to termination of pregnancy. The Practitioner,1989, vol 233 no 1472,pp990, 992.