Fumes from burning waste, DDT sprays affect the size, weight of unborn babies: NIH study

United Nations Children’s Fund (UNICEF) data show that globally, 20.5 million babies were born with low birth weight in 2015. That is, 14.6% of the 141 million babies born that year weighed less than 2.5 kilograms as opposed to their ideal weight of over 3.5 kilograms at birth.

Why is this important? Because most low birthweight babies don’t survive the first month of life. Those who do, suffer from lifetime health concerns like stunted growth, lower intelligence quotient (IQ), and early onset of chronic diseases like obesity and diabetes. Why is this in the news now? The US National Institutes of Health (NIH), one of the premier agencies for cutting-edge medical research globally, has linked the exposure of moms-to-be to “persistent organic pollutants” like the pesticide DDT and dioxins produced while burning municipal waste to low birthweight, despite a full-term, nine-month pregnancy. The scientists used ultrasound to determine the effects of foetal size in women who were 16-40 weeks pregnant.

DDT and dioxins in India

India is making strides in countering the malaria epidemic. One of the things we use to kill mosquitoes is DDT or Dichlorodiphenyltrichloroethane, a colourless, tasteless gas that was first used to fight mosquito-borne diseases during the Second World War! The flip side to this success story is, of course, the side-effects of DDT like low birth weight. To be sure, DDT isn’t the only POP at fault here. Others like dioxin - a product of burning municipal waste, natural resources or medical waste disposal - are just as potent though less known. According to recent estimates, India generates 1.5 lakh metric tonnes of solid waste daily. To be sure, many other factors like nutritional deficiencies among pregnant women also contribute to low birth weight. Up to 20% of all babies weigh under 2.5 kilograms at birth in India, according to one government estimate.

Link to pollution

Studies conducted in different parts of the world have shown that pollution in the environment has an inverse relationship with the birthweight among full-term newborns. A study conducted in Beijing during the 2008 Olympic Games found that moms-to-be who were in the eighth month of pregnancy during the Summer Games, (a month later) gave birth to babies who weighed 23 grams more than those who were born in 2007 or 2009. Air pollution levels had dropped remarkably in Beijing in 2008 as the government shut down industries, raised vehicle emissions standards, paused construction and slashed the number of vehicles on the road to half ahead of the Games. In California, US, scientists conducted a long-span study from 1996 to 2006 to understand the effect of ambient air pollutants like particulate matter smaller than 2.5 micron (a micron is one-thousandth of a millimetre) or PM2.5, PM10, carbon monoxide (CO), nitrogen dioxide (NO2) and ozone (O3) on foetal size, when pregnant women were exposed to them. The results showed that 2.3% of the infants born during the study period weighed under 2.5 kilograms. The scientists concluded that increased exposure of pregnant women to pollutants leads to an unusual decrease in the birthweight of their infants. They further added that though the strongest effects of pollutants were seen during the third trimester, they are equally harmful during the entire gestational period.

The NIH study 

Persistent Organic Pollutants or POPs are toxic chemicals like DDT (a pesticide; it is not used in agriculture in India now) and dioxin (formed by burning of municipal waste, natural resources or medical waste disposal or barrel burning) that remain in the environment for many years and can spread via the soil, water and air. A recent article in the peer-reviewed journal JAMA Pediatrics argued that POPs are one of the culprits for the low weight in newborns. The study was conducted in the US, where ultrasound scans of pregnant women enrolled in the NICHD Fetal Growth Study were analysed. Ultrasounds during the 16-40 weeks of pregnancy showed that pregnant women who were exposed to POPs during the second trimester had slightly smaller foetuses than women who hadn’t been exposed to these chemicals. The study further added that the growth of foetuses exposed to POPs was slower compared with foetuses who were not exposed to them. For more information, please read our section on Pregnancy: What to Expect and Things to Watch Out For. Health articles in Firstpost are written by myUpchar.com, India’s first and biggest resource for verified medical information. At myUpchar, researchers and journalists work with doctors to bring you information on all things health.