Another scare is born: electromagnetic fields and preemies

There was this press release, written from a small study, that went around the world... journalists at news syndicates wrote articles verbatim from the press release... the story grew as it was picked up by dozens of media outlets... the headline writers made each headline sound scarier and scarier... medical professionals and scientists hadn’t even seen the study yet, as it hadn’t been published, so no one could comment and by the time the study was published, it was old news and no one cared... and that’s how a scare is born.

This scare was directed at tiny, premature babies and their young parents who are already terrified and anxious for the safety and survival of their newborns. That makes it cruel and wrong — especially when the study didn’t show anything to support the “what-if” scare mongering, and there is no credible evidence or biological plausibility to cause parents such worries.

The scare: telling parents that the very thing that is helping to keep their tiny babies alive and offer them the best chances to grow could be damaging their hearts and worsening their outcomes... because of EMF (electromagnetic fields) from their incubators.

The public was told that “heart variability decrease means a poor outcome in adult patients with heart disease,” which made the danger sound ominous, indeed. But premature babies are not adults.

Background: Premies are very special little people

Before looking at this study, it may be helpful to take a peek inside a neonatal intensive care unit (NICU) and the life of a tiny premature baby. Then, you’ll be able to quickly see in this study the flaws mainstream media and the journal’s peer-reviewers chose to ignore.

NICUs can provide the highly specialized care that sick babies or those born premature need. One of the most important things to the survival of a premature baby is temperature regulation. These little ones have little or no body fat to keep them warm, to make heat or insulate them from temperature fluctuations. Yet they have a large surface area to body mass which greatly increases their heat loss. Their skin is immature, fragile and permeable, which increases evaporative water loss. Premies don’t sweat and can overheat quickly. And they don’t shiver, either, with the littlest ones not able to move around to help raise their body temperatures.

Babies who are able to be moved from the overhead warmer beds (which are necessary when they’re most critical and nurses and doctors need to be able to reach them more easily) are placed in incubators. Incubators provide a carefully controlled environment that adjusts the inside temperature (servo-controlled) to keep a baby’s temperature normal, and gently circulates the warm air. Simultaneously, they provide a humidified environment to minimize evaporative heat loss and shield the baby from windchills. Incubators aren’t just for comfort. Incubators are one of the most critical and necessary means to help them survive and grow. In fact, with the development of incubators came enormous decreases in mortalities of premies. Incubators are so important that they’re a medical device and all incubators must meet strict FDA safety and manufacturing standards. Even the materials used must be tested and shown safe, with benefits that exceed potential risks.

Any stress, including cold stress, in a tiny premature baby increases their metabolism, resulting in weight loss or failure to grow, increases use of limited energy reserves, and can quickly deplete their glycogen stores and cause life-threatening hypoglycemia. Stress can also lead to metabolic acidosis which decreases the production of surfactant in their lungs and the number of alveoli (air sacs), resulting in hypoxia and insufficient oxygenation to their developing brain and neurological system and to their gut. Hypoxia also causes pulmonary vasoconstriction which further worsens the hypoxia. Stress can also lead to more apnea and bradycardia spells.

Premature babies aren’t just tiny, their autonomic nervous systems are underdeveloped, too. They are easily startled. The slightest sudden change or stimulus can cause a notable reaction in their heart rates, blood pressures and oxygenation. Imagine how you feel when you’ve had the scare of your life and been frightened half to death and imagine that reaction with an immature nervous system and you can see how startling them can affect their health. After a scare, it can take them awhile to settle back down and stabilize again, especially the most premature ones.

So, incubators also provide a protected cocoon for these little babies that helps to minimize other stresses, such as the noises of the busy NICU. The incubators are often covered to keep them darkened and free from the bright lights. The babies are often placed on sheep skin and nestled in soft bed rolls to help them feel secure and not flail around, to help them rest more quietly. Sometimes tapes of their mother’s heartbeats or parents’ voices will be played softly inside the incubator to help soothe them, when their parents aren’t able to be with them to provide that much needed love and comfort. The nursing staff tries hard to minimize stress on these tiny babies to enable them to spend most of their energy growing and developing and to help keep them stable. Procedures and interruptions are kept to a minimum.

In premature babies, autonomic nervous system instability, clearly, is most related to their gestational age, maturity of their nervous system, and to the degree to which they’ve been stressed. Heart rate variability (how far the heart rate goes up and down from baseline) is a measure of this. The high-component is mainly modulated by the parasympathetic nervous system; the low-component is modulated by the sympathetic and parasympathetic nervous system. The high/low ratio (LF/HF) is used to evaluate this balance.

This effect has been shown in studies of kangaroo care, for example. This is a technique of using mothers to hold their premies between their breasts, skin-to-skin, and was developed by a neonatologist in Bogota, Columbia, out of necessity when they had no access to electricity or incubators. It reduced mortality form 70% to 30%. In studies of it led by professor Gail C. McCain, Ph.D., RN, FAAN, at the University of Miami, Coral Gables, Florida, by lowering stress in healthy premies, their heart rate variability was reduced.

Incubators and heart rate variability

A study just published in the Fetal and Neonatal Edition of Archives of Disease in Childhood — the online, not print version — set out to “verify whether the exposure to incubator motor electric power may alter autonomic nervous system activity in newborns.” It was led by Dr. Carlo V. Bellieni, at the University of Siena in Italy.

It opened with a lengthy discussion of purported health concerns about electromagnetic fields (EMFs), such as repeating the fear that cell phones and power lines cause childhood leukemia and adult brain cancers. [Dr. John W. Farley, Ph.D., a physicist at the University of Nevada, Las Vegas, reviewed the science and evidence surrounding this unsupported fear here.] EMFs are emitted while incubator motors are running. The authors said, however, that they’d previously shown the EMF levels in the incubators they used were all within International Commission on Non-Ionizing Radiation Protection (ICNIRP) safety guidelines — over 10mG — (which, by the way, was 5 to 30 times below studies they exampled as suggesting health effects).

In their earlier 2003 study, they’d speculated that EMFs in incubators could block the antioxidant, melatonin, and put babies at “risk of brain damage, due to free radicals produced by pre- and perinatal hypoxic-ischaemic distress,” and called for international laws on EMF exposure for newborns. JFS readers will remember that this was the period when the European Union Commission was working on its electromagnetic fields directive issued in 2004, which set “safe” limits on radiation exposure for healthcare workers so low that it eliminated the use of MRIs.

For this study, the researchers chose 27 babies in the NICU in incubators who were free from major malformations, intraventricular hemorrhages of grade III+, seizures, bradycardia or tachycardia. The babies were fed and placed on their backs for one hour. The babies were quiet and awake or in active sleep or quiet sleep. Electrodes were applied to their chests and their heart rates were recorded for 5 minutes, the incubator motor was then turned off for 5 minutes, and then turned back on for another 5 minutes. The heart rate variability for each 5-minute period was recorded. They primarily examined the LF/HF ratio because it is used to “assess a predominant shift in the sympatho-parasympathetic balance, which has been hypothesized to be correlated with sudden infant death,” and, they said, would be a measure of the effects of EMFs produced by incubators on this sympatho-parasympathetic balance.

They said vibration levels from the motors were undetectable. The babies’ gestational ages ranged from 24 weeks to 36 weeks.

Did you identify any flaws in the study design so far?

24 to 36 weeks is a huge variation in gestational ages and especially of autonomic nervous system maturity. But they didn’t reveal how many babies at which ages they chose to test for each experimental group, nor did they separate LF/HF ratios by maturity levels.

They didn’t explain why they chose such brief periods to record heart rates. If you were designing an experiment to test the influences of a motor, is 5 minutes after disturbing a preemie long enough to separate the startle effect from the motor’s EMFs?

They realized after this first experiment (Experiment #1) that the motor noise could be influencing their findings, so they made a tape recording of the incubator fan and played it while the motor was off for the second experiment on a different group of 16 babies (Experiment #2).

Here are just a few of the other confounding factors not controlled for in the study design that are known to affect heart rate variability in newborns and premature babies. (Remember, this wasn’t a randomized trial, so we also don’t know what factors might have played a role in the selection of the babies in each of the groups.)

· Pacifier use: Healthy preterm babies show less heart rate variability and more autonomic stability with pacifier use, especially as they mature and transition from gavage to oral feedings.

· Maternal substance abuse: Cocaine or other drug use during pregnancy affects their baby’s heart rate variability.

·Sepsis: A baby that is septic (has an infection) has reduced heart rate variability. Recovering from sepsis in a newborn is accompanied by significant increases in heart rate variability, but not by large changes in heart rate.

· Light exposure: Newborns stimulated by being exposed to changes in illumination show significant increases in heart rate variability.

· Active or quiet sleep: Sleep state affects heart rate variability in premies.

· Respiration and oxygenation: Ventilation and the amplitude of breaths may affect heart rate variability in babies, as can breathing rate and oxygenation.

· Positioning and bedding: Similarly, a preemie positioned on his/her tummy or on his/her side and cuddled by blanket rolls flails less and is less stressed and stimulated, affecting heart rate variability.

· Gestational Age, birthweight and days since birth: Maturation of the baby and of his/her autonomic nervous system is one of the most significant factors in heart rate variability of premies.

· Mattress thickness and distance from motor: As the authors have previously reported, EMF exposure can be changed and is related to the thickness of the mattress and bedding, and distance from the incubator motor.

Findings

In Experiment #1, the LF/HF ratios went from ranges of 0.5-2.0 during the initial 5 minutes to 0.3-2.9 when the motor was turned off, but the change was “not to a significant extent,” they wrote. So, turning the motor off (and presumably the EMFs) had no real effect on heart rate variability. When the motor was turned back on, however, the ratio jumped the most, to a range of 1.8-3.5. This was a group of babies where the motor noise wasn’t controlled for, illustrating how being startled by the sudden return of a motor noise affected their nervous systems.

In Experiment #2, where a tape recording of the noise was played while the motor was off, there was “no significant changes in heart rate variability” throughout the playing of the tape. All LF/HF ratios averaged 1.2, with similar ranges. [The image shows the ratios during the 1^st, 2^nd, and 3^rd 5-minute periods.]

Notice that they did not repeat the first experiment on the same group of babies, actually turning the motor on and off to determine EMF effects while also controlling for the noise change by playing a tape. Instead, they made the jump to conclude that playing a tape for a different group of babies proved it was EMFs that accounted for the changes in the first noise-uncontrolled group. They didn't show anything related to EMFs.

Yet, they concluded:

Our study showed that an EMF present in neonatal incubators can alter HRV [heart rate variability] in newborns, though other studies, with some exceptions, did not find similar effects in adults... The LF/HF ratio is higher in preterm infants than in adults; but this may be influenced by the electromagnetic environment, leading to the need for new studies on babies not exposed to an EMF...

What this study adds: Electromagnetic fields generated by incubators can alter heart rate variability in newborns. This is a sign of an influx of electromagnetic fields into the newborns’ autonomic system.

But they showed no correlation between EMF and heart rate variability! [How many people will read the abstract and never look to see what the study data actually showed? How often will this study be cited, with no one actually reading it?]

They then went on to say that “even caregivers should be concerned about the risks of EMF, since they are exposed to peaks of >10 mG when close to the incubators,” and recounted levels from computer monitors and power lines. “International recommendations and laws set levels to safeguard the health of workers exposed to EMFs,” they wrote, “newborns should be worthy of similar protection.” They closed by saying that prudent avoidance of EMF is warranted in newborns “because no study has so far excluded the possibility of negative consequences of their chronic exposition to a high EMF in incubators.” In other words, science cannot prove a negative, so we should assume there is a risk and act on it with no evidence. And be scared.

Once again, anytime you hear something that makes you feel afraid, you know your emotions are being played and that’s your alert that what you’re hearing is not impartial science. Your other clue is when the media all reports the same story, nearly verbatim, all at the same time — it’s evidence of science by press release. To all of those young parents of premature babies, this is another concern you don’t need. This study provided no evidence for worry.

© 2008 Sandy Szwarc

Having a baby in the NICU can be such a stressful, overwhelming time for new parents, but there are a lot of resources with generally much better information than you’ll find in mainstream media. Prematurity.org, a parental support group, offers a series of articles to help families get through the NICU experience, here. Dr. Kirsi Dyer, M.D., a former NICU parent, also has a support blog for NICU parents, here. The March of Dimes offers several guides for helping parents cope with the natural emotional rollercoaster; those can be found here.

5/3/08: Edited for clarity.