Air Pollution Reduces Fetus Size and Decreases Male/Female Ratio

Monday, February 18, 2008 by: Tom Mosakowski
Tags: air pollution, health news, Natural News

(NewsTarget) A study by researchers at Queensland University in Brisbane, Australia warns that women exposed to air pollution in urban areas during pregnancy have smaller fetuses than those in areas with cleaner air. This is the first study to show that air pollution affects fetal development.

The air pollution of concern is from urban areas, which tends to be mainly caused by automobile emissions, especially sulphur dioxide from diesel engines. Nitrogen dioxide and particulate matter from automobile engines are also included.

Dr. Adrian Barnett suggests that women seriously consider reducing their exposure to this form of air pollution during pregnancy. Those who live near major roads are most at risk.

The study compared fetus sizes of 15,000+ ultrasound scans to levels of air pollution in different areas within a 14 km radius of downtown Brisbane. The fetuses were between the 13th and 26th weeks of development.

Dr. Barnett said, "If the pollution levels were high, the size of the fetus decreased significantly."

Quantitative measurements of head and abdominal circumference and femur length were smaller in areas of higher pollution (http://www.ehponline.org/docs/2007/10720/abs...) .

These results are important because fetus size is a positive determinant of birth weight and bigger babies have been shown to be healthier and have higher IQs in childhood and adulthood.

How much the air pollution affects the mother which then affects the fetus versus affecting the fetus directly while inflicting negligible harm to the mother is unknown, but it is a safe bet that air pollution is not safe for human development at any stage: fetal, child or adult.

Nitrogen dioxide has been linked to Sudden Infant Death Syndrome (SIDS) by University of California, San Diego researchers in a 2005 study. SIDS is characterized by the sudden and unexplainable death of a seemingly healthy infant aged one month to one year (http://adc.bmj.com/cgi/content/abstract/90/7...) .

Furthermore, a 2004 study by researchers from Sao Paulo University in Brazil found that fewer boys were born in polluted areas. Female fetuses tend to be more apt at surviving harsh conditions in the womb and during birth. In areas with the least pollution, 51.7% of the babies born between January 2001 and December 2003 were male. In the most polluted areas, 50.7% were male.

The researchers in Brazil did another study with male rats in filtered and unfiltered ambient air. After four months of these conditions, the male rates were mated with female rats not exposed to pollution. Males from the filtered air produced young of a 1.34 male/female ratio. Males from unfiltered air produced young of a 0.86 male/female ratio. Some hypotheses that can be drawn from these results are that pollution increases the ratio of female/male sperm produced, pollution damages male sperm more than female sperm, or that both are damaged the same amount but males are less able to withstand the damage. The exact mechanism is unknown.

Many observations have been made about conditions that affect the ratio of male to female births. Theories have been made as to why a changed ratio is beneficial to a species. Some are mentioned here
(http://en.wikipedia.org/wiki/Sex_ratio) .

Other notable links:

(http://www.pubmedcentral.nih.gov/articlerend...)

(http://www.epa.gov/air/criteria.html)

About the author

Tom Mosakowski, B.S. Biochemistry.