(Press-News.org) Cincinnati, OH. July 26, 2012 – Congenital hypothyroidism is thyroid hormone deficiency at birth that, if left untreated, can lead to neurocognitive impairments in infants and children. Although the World Health Organization recommends 200-300 µg of iodine daily during pregnancy for normal fetal thyroid hormone production and neurocognitive development, the US Institute of Medicine considers 1,100 µg to be the safe upper limit for daily ingestion. A case series scheduled for publication in The Journal of Pediatrics describes three infants who developed congenital hypothyroidism as a result of excess maternal iodine supplementation.
Kara Connelly, MD, and colleagues from Oregon Health & Science University, Doernbecher Children's Hospital, Boston University School of Medicine, State of Oregon Public Health Laboratory, and Randall Children's Hospital at Legacy Emanuel describe three infants with congenital hypothyroidism whose mothers had taken 12.5 mg of iodine daily, 11 times more than the safe upper limit, while pregnant and/or breastfeeding. Iodine is transferred from the mother to the infant through the placenta or breast milk. The three infants had blood iodine levels 10 times higher than healthy control infants (measured from newborn screening filter paper).
Excess iodine causes the thyroid to temporarily decrease function to protect against hyperthyroidism (Wolff-Chaikoff effect). Adults and older children are able to "escape" from this effect after several days of excess iodine to avoid hypothyroidism. However, the immature thyroid glands of fetuses and newborns have not developed this protective effect and are more susceptible to iodine-induced hypothyroidism. Although infants recover normal thyroid function after acute iodine exposure (e.g., a few days of topical iodine application), continuous excessive iodine exposure to the fetal and neonatal thyroid gland may cause long-term harmful effects on thyroid function.
Sources of iodine include nutritional supplements, prenatal vitamins, and seaweed (kelp). According to Dr. Connelly, "The use of iodine-containing supplements in pregnancy and while breastfeeding is recommended in the United States. However, these cases demonstrate the potential hazard of exceeding the safe upper limit for daily ingestion." Excess iodine ingestion from supplementation is often unrecognized because it is not routine practice to ask mothers of infants with congenital hypothyroidism about nutritional supplements taken during pregnancy. Pregnant or breastfeeding women should discuss the safe dosages of nutritional supplements with their doctors prior to including them in their daily regimen.
###
Notes for editors
"Congenital Hypothyroidism Caused by Excess Prenatal Maternal Iodine Ingestion" by Kara Connelly, MD, Bruce Boston, MD, Elizabeth Pearce, MD, David Sesser, David Snyder, MD, Lewis Braverman, MD, Sam Pino, Stephen LaFranchi, MD, appears in The Journal of Pediatrics (www.jpeds.com), DOI 10.1016/j.jpeds.2012.05.057, published by Elsevier.
For an interview with Kara Connelly, MD, contact Tamara Hargens-Bradley, +1 503 494 8231, hargenst@ohsu.edu.
About the Journal of Pediatrics
The Journal of Pediatrics is a primary reference for the science and practice of pediatrics and its subspecialties. This authoritative resource of original, peer-reviewed articles oriented toward clinical practice helps physicians stay abreast of the latest and ever-changing developments in pediatric medicine. The Journal of Pediatrics is ranked 4th out of 113 pediatric medical journals (2011 Journal Citation Reports, Thomson Reuters 2012). URL: www.jpeds.com
About Elsevier
Elsevier is a world-leading provider of scientific, technical and medical information products and services. The company works in partnership with the global science and health communities to publish more than 2,000 journals, including The Lancet and Cell, and close to 20,000 book titles, including major reference works from Mosby and Saunders. Elsevier's online solutions include ScienceDirect, Scopus, Reaxys, ClinicalKey and Mosby's Nursing Suite, which enhance the productivity of science and health professionals, and the SciVal suite and MEDai's Pinpoint Review, which help research and health care institutions deliver better outcomes more cost-effectively.
A global business headquartered in Amsterdam, Elsevier employs 7,000 people worldwide. The company is part of Reed Elsevier Group PLC, a world-leading publisher and information provider, which is jointly owned by Reed Elsevier PLC and Reed Elsevier NV. The ticker symbols are REN (Euronext Amsterdam), REL (London Stock Exchange), RUK and ENL (New York Stock Exchange).
Media contact
Monica Helton
+1 513 636 7140
journal.pediatrics@cchmc.org
Study associates excess maternal iodine supplementation with congenital hypothyroidism in newborns
2012-07-26
ELSE PRESS RELEASES FROM THIS DATE:
Teamwork against Benzene
2012-07-26
This press release is available in German.
Leipzig. The carcinogenic harmful substance benzene can seriously impact the soil and ground water following chemical accidents or at old industrial sites. Nevertheless, bacteria exist which can degrade this compound even in the absence of oxygen. Until now it was not clear which organisms take part in this process and how they work together. With modern analytical procedures scientists of the Helmholtz Centre for Environmental Research (UFZ) have succeeded for the first time in tracking the path of this harmful substance through ...
New stroke treatments becoming a reality
2012-07-26
Scientists led by the President of The University of Manchester have demonstrated a drug which can dramatically limit the amount of brain damage in stroke patients.
Professor Dame Nancy Rothwell, Professor Stuart Allan and their team have spent the last 20 years investigating how to reduce damage to the brain following a stroke.
They have been testing the effectiveness of the drug Anakinra (IL-1Ra), which is already used for rheumatoid arthritis in experimental studies of stroke.
This new study builds on previous research, although the big difference is that rats ...
Switching the state of matter
2012-07-26
Sixty years after the transistor began a technological revolution that transformed nearly every aspect of our daily lives, a new transistor brings innovations that may help to do so again. Developed at RIKEN, the device uses the electrostatic accumulation of electrical charge on the surface of a strongly-correlated material to trigger bulk switching of electronic state. Functional at room temperature and triggered by a potential of only 1 V, the switching mechanism provides a novel building block for ultra low power devices, non-volatile memory and optical switches based ...
A pulsar with a tremendous hiccup
2012-07-26
This press release is available in German.
Pulsars are superlative cosmic beacons. These compact neutron stars rotate about their axes many times per second, emitting radio waves and gamma radiation into space. Using ingenious data analysis methods, researchers from the Max Planck Institutes for Gravitational Physics and for Radio Astronomy, in an international collaboration, dug a very special gamma-ray pulsar out of data from the Fermi Gamma-ray Space Telescope. The pulsar J1838-0537 is radio-quiet, very young, and, during the observation period, experienced the strongest ...
New biomarker for common lung cancer predicts responses to chemotherapy
2012-07-26
Patients with the most common type of lung cancer are notoriously insensitive to chemotherapy drugs, including cisplatin. New findings related to the cellular pathways that regulate responses to cisplatin have now been published by Cell Press on July 26th in the journal Cell Reports. The findings reveal a potential biomarker that can be used to predict how these patients will respond to chemotherapy, as well as the patients' overall prognosis, paving the way for personalized treatment strategies.
Non-small cell lung cancer (NSCLC) is one of the leading causes of cancer-related ...
Methane measurements at low level flight
2012-07-26
A team of scientists from the Alfred Wegener Institute for Polar and Marine Research in the Helmholtz Association (AWI) and the GFZ German Research Centre for Geosciences has just completed an airborne measurement campaign that allowed for the first time to measure large-scale methane emissions from the extensive Arctic permafrost landscapes. The study area extended from Barrow, the northernmost settlement on the American mainland, across the entire North Slope of Alaska, to the Mackenzie Delta in the Northwest Territories of Canada. The airborne measurements (Airborne ...
Unprecedented accuracy in locating brain electrical activity with new device
2012-07-26
Researchers at Aalto University in Finland have developed the world's first device designed for mapping the human brain that combines whole-head magnetoencephalography (MEG) and magnetic resonance imaging (MRI) technology. MEG measures the electrical function and MRI visualizes the structure of the brain. The merging of these two technologies will produce unprecedented accuracy in locating brain electrical activity non-invasively.
We expect that the new technology will improve the accuracy of brain mapping of patients with epilepsy. It may also improve the diagnosis of ...
DNA damage in roofers due to PAH exposure – possible cancer link
2012-07-26
Roofers and road construction workers who use hot asphalt are exposed to high levels of polycyclic aromatic hydrocarbons (PAHs). A University of Colorado Cancer Center study published this week in the British Medical Journal Open shows that roofers have higher PAH blood-levels after a shift than before and that these high levels of PAHs are linked with increased rates of DNA damage, and potentially with higher cancer risk.
"We've known for some time that roofers and road workers have higher cancer rates than the general population, but we also know roofers have a higher ...
Deadly E. coli strain decoded
2012-07-26
EAST LANSING, Mich. — The secret to the deadly 2011 E. coli outbreak in Germany has been decoded, thanks to research conducted at Michigan State University.
The deadliest E. coli outbreak ever, which caused 54 deaths and sickened more than 3,800 people, was traced to a particularly virulent strain that researchers had never seen in an outbreak before. In the current issue of the academic journal PLoS ONE, a team of researchers led by Shannon Manning, MSU molecular biologist and epidemiologist, suggests a way to potentially tame the killer bacteria.
The strain, E. coli ...
'Basarab' surname may not indicate direct relation to Vlad the Impaler
2012-07-26
WASHINGTON—A study by the Genographic Project has shown that not all individuals carrying the Romanian "Basarab" surname, the first dynasty of Wallachian kings that included the real-life Dracula, can be direct biological descendants of the Basarab dynasty.
The Basarab dynasty ruled Wallachia, the historical and geographical southern region of present-day Romania, for almost three centuries (1330-1601) and had among its members Vlad III the Impaler, commonly known as Dracula. The ethnic origin of the Basarab family has long been a dispute among historians, with both an ...