Published May 13, 2012

      Two decades ago, the womb could well serve its function of sheltering the developing baby from the environment.

      It had been 40 years since X-rays had been found to be the cause of the epidemic of childhood leukemia. Healthy, drug-free mothers rarely produce children with disabilities.

      Year by year since the early 1990s, the influence of the external environment on this once safe place for development has grown — wifi, wireless phones, medical monitoring. In that same 20 years, the number of children with disabilities has grown at a steady and alarming rate.

      In March, the Centers for Disease Control and Prevention reported one in six U.S. children has a learning disability and one of every 54 boys is autistic.

      Most expectant women now take the precaution of keeping phones and computers away from their abdomens. Few would think the ultrasound devices used by their physicians would not be safe. Most physicians also consider such devices to be inherently harmless.

      I am a retired engineer with experience in heat and vibration. A year ago, I watched a PBS special on the autism epidemic and made what I think is a logical connection to ultrasound as the cause.

      In investigating the topic, I found a sparse amount of scientific investigation. The most alarming thing I found is that in 1992, an eightfold increase in the intensity was approved without scientific study that it was safe. The decision is characterized in a scientific paper as a risk assessment. The safety still has not been proven.

      Conversely, there is no proof that the approved exposure levels are unsafe. There is, however, a wealth of evidence that overexposure can cause cell damage and brain damage. In brain development, cells not only grow but also migrate to the appropriate location.

      Abnormal distribution of cells is a characteristic of autistic brains. The ways that overexposure can occur are many:

      • Devices malfunction. In Sweden, 40 percent of 676 hospital imaging ultrasounds were not operating within specifications. A U.S. study of therapeutic ultrasounds found one-third to be out of calibration. Used ultrasounds are sold on eBay;

      • Operators err. Surveys of operators have found an appalling lack of knowledge of the safety guidelines. Many operators are self-taught;

      • Guidelines ignored. Ultrasound devices are considered benign. People are unaware there is a danger of vibration and subsequent heating. Every year, the number of scans per pregnancy increases. Photography studios make keepsake videos.

      There is no need for ultrasound in a normal pregnancy. Before you have one or administer one, ask yourself, “How can it be a good idea to vibrate and perhaps heat brain cells that are not only developing but migrating into position?”

      Everything I have found is on a website, www.ultrasound-auti

      sm.org. Research will take years. My most recent request of the Food and Drug Administration is for a field evaluation of ultrasounds in prenatal use. If calibration is found to be a problem, the FDA could quickly issue an alert.

      Parrish Nelson Hirasaki is a retired engineer. She lives in Dickinson.

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