Pregnant women exposed to persistent organic pollutants (POPs) may be at greater risk of giving birth to slightly smaller fetuses according to a study by researchers at the US National Institutes of Health. This is the most comprehensive study of these compounds in relation to pregnancy ever conducted in recent years.
According to these results, these chemicals, which were once used in agriculture but have persisted for years in the environment, even at low levels of exposure can have lasting effects. These substances have been used in agriculture and are still used in some industrial processes. Among the products containing them are DDT and dioxin.
The particularity of these chemicals lies in their slow degradation. This means that they can persist in water and air for many years and can also enter the food chain and thus our bodies. In the past, these compounds had already been linked to certain reproductive disorders and increased risks of birth defects.
This study investigated fetal growth measures in pregnant women exposed to these substances unlike other studies that had mostly taken into account the size at birth, as explained by Pauline Mendola, researcher at the National Institute of Child Health Human Development Eunice Kennedy Shriver and author of the study published in JAMA Pediatrics. The researcher analyzed blood test data from 2284 pregnant women for weeks of pregnancy from the 16th to the 40th.
These data were then compared with measurements of the growth of the head circumference, abdomen and length of the fetal femur. The researcher found that compared to fetuses of mothers with lower exposure to organochlorine pesticides, those with higher exposure showed more widespread growth reductions and a reduction in head circumference of 4.7 mm on average as well as abdominal circumference (3.5 mm) and femur length (0.6 mm).
The researcher also found similar data regarding exposure to polychlorinated biphenyls (dioxin-like substances) with an average reduction in head circumference of 6.4 mm and abdomen circumference of 2.4 mm. On the other hand, as regards exposure to polybrominated diphenyl ethers (flame retardants used in various consumer products), the latter were associated with an average abdominal circumference reduction of 2.4 mm and an average femur length reduction of 0.5 mm.