According to a study published in the journal Environmental International, pregnant women should think twice before eating a cheeseburger or a boxed pastry. Surprisingly, the report focuses not on the food itself, such as fries, burgers, shakes, and cakes, but on what comes into contact with the meal before it is consumed. Research shows that phthalates, a class of chemicals associated with plastics, can shed from the wrapping, packaging and even from plastic gloves worn by food handlers into food. Once consumed during pregnancy, the chemicals can get into the bloodstream, through the placenta and then into the fetal bloodstream.

The chemical can cause oxidative stress and an inflammatory cascade within the fetus, researchers noted. Previous literature has indicated that exposure to phthalates during pregnancy can increase the risk of low birth weight, preterm birth and child mental health disorders such as autism and ADHD. This is the first study in pregnant women to show that diets higher in ultra-processed foods are linked to greater phthalate exposures, the authors wrote, "When moms are exposed to this chemical, it can cross the placenta and go into fetal circulation," said senior author Dr. Sheela Sathyanarayana, a UW Medicine paediatrician and researcher at the Seattle Children`s Research Institute. This analysis involved data in the Conditions Affecting Neurocognitive Development and Learning in Early Childhood (CANDLE) research cohort, which comprised 1,031 pregnant individuals in Memphis, Tenn., who were enrolled between 2006 and 2011. Phthalate levels were measured in urine samples collected during the second trimester of pregnancy.