Search This Blog

Sunday, January 10, 2010

Are They Safe? The Risks of Prenatal Ultra Sounds

"The authors found that almost 1 in 5 of all pregnant women -- including those at low-risk of complications -- now receive 4 or more ultrasounds in the second and third trimesters."

While the article below seems to worry more about higher anxiety levels, invasive procedures such as amniocentesis and increasing health care costs - which is not to be poo poohed and definitely warrants some concern- they have left out the very real dangers of prenatal Ultra Sounds.


Ultra Sounds during pregnancy can not be assumed to be safe. Scientific work in Norway followed up on children at age eight or nine, born of mothers who had taken part in two controlled trials of routine ultrasound in pregnancy, they were able to show that routine ultrasonography was associated with a symptom of possible neurological problems.

An editorial in Lancet, A British medical journal, stated: "There have been no randomized controlled trials of adequate size to assess whether there are adverse effects on growth and development of children exposed in utero to ultrasound. Indeed, the necessary studies to ascertain safety may never be done, because of lack of interest in such research".

On top of that, there are no national or international standards for the output characteristics of ultrasound equipment. The result is the shocking situation described in a commentary in the British Journal of Obstetrics and Gynaecology, in which ultrasound machines in use on pregnant women range in output power from extremely high to extremely low, all with equal effect. The commentary reads, "If the machines with the lowest powers have been shown to be diagnostically adequate, how can one possibly justify exposing the patient to a dose 5,000 times greater?". It goes on to urge government guidelines on the outut of ultrasound equipment and for legislation making it mandatory for equipment manufacturers to state the output characteristics. As far as is known, this has not yet been done in any country. Safety is also clearly related to the skill of the ultrasound operator. At present, there is no known training or certification for medical users of ultrasound apparatus in any country.

As the FDA warned in 2004, "ultrasound is a form of energy, and even at low levels, laboratory studies have shown it can produce physical effect in tissue, such as jarring vibrations and a rise in temperature." This is consistent with research conducted in 2001 in which an ultrasound transducer aimed directly at a miniature hydrophone placed in a woman's uterus recorded sound "as loud as a subway train coming into the station."

A rise in temperature of fetal tissue might not seem alarming, but temperature increases can cause significant damage to a developing fetus's central nervous system, according to research. Across mammalian species, elevated maternal or fetal body temperatures have been shown to result in birth defects in offspring. An extensive review of literature on maternal hyperthermia in a range of mammals found that "central nervous system (CNS) defects appear to be the most common consequence of hyperthermia in all species, and cell death is believed to be one major explanation for these effects."

In fact, the FDA and professional medical associations know that prenatal ultrasound can be dangerous to humans, which is why they have consistently warned against the non-medical or "keepsake" ultrasound portrait studios that have cropped up in malls throughout the country.

The risks to the baby are potentially higher in commercial enterprises due to the higher acoustic output required for high-definition images, a potentially long session—as technicians hunt for suitable images—and the employment of ultrasound operators who may have no medical background or appropriate training. Meanwhile across North America 3 & 4D ultrasounds have become the "rage", with parents paying hundreds of dollars to have a videos and fancy 3 dimensional images of their unborn baby. Some parents gush that it helps them to bond to their babies before they are born...... But is this "bonding" really worth the risks?

When you combine the unknown factors of prenatal ultra sounds on the growing fetus and the fact that the known risks are making many professionals questions the risk/benefit ratios, with the facts that more and more studies are showing that most U/S's are not changing neonatal outcomes.... maybe we need to question the reason we are having them. I have always had an early first trimester U/S with all of my pregnancies. I convinced my self that these were necessary because of my history of early first trimester miscarriages... I "needed" to know that the pregnancy was viable, that my baby had a heart beat and was thriving. Then of course there was the second trimester Ultra Sound to test for various chromosomal and birth defects. Then the doctor wants to do another one in the third trimester to measure the baby, oh and another one the moment you go past 40 weeks gestation to measure the baby again and the amniotic fluid levels ...and perhaps a 5th after 41 weeks gestation.... you know... just to check everything again.....

All of a sudden what began as a low risk, totally normal pregnancy has been turned into cascade of medical interventions before labour even begins. Never mind the three ring circus of Labour & Delivery in the average hospital that your baby will be put through before it even gasps it's first breath. Where do we draw the line? Making decisions for our childrens health and best interests are the most difficult choices a parent will ever make. As parents we need to educate our selves because only an educated choice is an informed choice. And some choices are too important to leave up to others.

Further reading on Ultra Sounds

Prenatal Ultrasonography Has Increased 55 Percent for Pregnant Women, Even in Low-Risk Pregnancies

ScienceDaily (Jan. 5, 2010) — Current use of prenatal ultrasounds in women with singleton pregnancies is 55% greater than in 1996, even in low-risk pregnancies. More than one-third (37%) of pregnant women now receive 3 or more ultrasound tests in the second and third trimesters of a given pregnancy, according to an article in CMAJ (Canadian Medical Association Journal). The increase in the use of multiple ultrasound scans per pregnancy has been more pronounced in low-risk than high-risk pregnancies, suggesting a need to review current practices.

Current guidelines recommend two ultrasounds in an uncomplicated pregnancy -- one in the first trimester and one in the second to screen for fetal and genetic anomalies.

The study included almost 1.4 million singleton pregnancies between 1996 and 2006 in Ontario, Canada's most populous province. It included both low-risk and high-risk pregnancies, the latter defined by the presence of a maternal comorbidity, need for genetics counselling or a prior complicated pregnancy. The study accounted for the recent introduction of first trimester nuchal translucency scanning.

The authors found that almost 1 in 5 of all pregnant women -- including those at low-risk of complications -- now receive 4 or more ultrasounds in the second and third trimesters.

"Our findings are consistent with a growing body of evidence suggesting that some health interventions most beneficial to high-risk individuals are frequently directed at apparently low-risk populations," write Dr. John You of McMaster University and coauthors.

Obstetricians practice in the highest medical-legal risk environment and may feel the need to reassure patients with a safe and relatively cost-effective ultrasound test.

"While the benefits of prenatal ultrasound in high-risk pregnancies may be more clear, the value of repeat ultrasounds in low-risk patients is not," write the authors. Since the detection of minor benign findings is increasingly more common with technological advances such as pregnancy ultrasound, they can cause anxiety and lead to invasive procedures such as amniocentesis. Increasing screening in low-risk women may also be contributing to increasing health care costs.

The authors conclude that more judicious use of prenatal ultrasounds in low-risk women is required, but there should be careful discussion over the best approach to balance frequency and medical need.

READ the original article HERE