Pollution linked to birth defects
Reported 19th July 2011
Maternal exposure to coal smoke and pesticides severely increases the likelihood of giving birth to deformed babies, according to a recent Chinese study.
The researchers focused on mothers living in one of central China’s coal-producing regions, Shanxi province, and found birth defects usually connected with folic acid deficiency, maternal obesity, and maternal diabetes.
The relationship between birth defects and environmental pollution due to coal mining has been given comparatively little attention, though doctors have long suspected that a link must exist.
The researchers measured the levels polycyclic aromatic hydrocarbons (PAHs) and synthetic pesticides in the placentas of the women who took part in the study.
They found high levels of the synthetic pesticides DDT, hexachlorocyclohexane, and endosulfan.
Lead researcher Tong Zhu, of the Beijing University labratory for environmental simulation and pollution control, said that pollutants could readily cross preplacental structures and potentially have an effect on embryonic development.
For the study, the researchers analysed the placentas of 80 babies and aborted foetuses showing neural tube defects (NTDs), and compared them to the placentas of 50 babies that were born without defects.
NTDs are a type of birth defect affecting the brain and spinal cord, and babies born with NTDs usually end up stillborn, or else die shortly after birth.
The researchers focused on pregnant women in counties of northern Shanxi where the rate of NTDs is unusually high.
In those places, 14 out of every 1,000 babies is born with an NTD.
The researchers found that women exposed to high levels of PAHs were over 400% more likely to give birth to babies with NTDs, and that women forced to cope with higher-than-average levels of pesticide exposure were 3 times as likely to give birth to babies with NTDs.
Zhu said women should avoid coal smoke and use cleaner fuels for heating and cooking.
China relies heavily on coal for power production, and its coal industry is the largest and deadliest in the world.
Thousands of people die each year in Chinese coal mines, and Chinese coal production is currently rising year on year.
NTDs are also found in more developed countries, albeit at a lower rate.
The most common NTD involves the spinal column failing to close during the first month of pregnancy, resulting in a baby born paralysed.
In another common NTD, the neural tube fails to close near the head, and the brain does not fully develop.