What DINCH is and where it is found

The DINCH plasticizer birth weight question starts with the chemical itself: DINCH, formally named 1,2-cyclohexane dicarboxylic acid diisononyl ester, is a plasticizer used to make plastic more flexible and durable. It is marketed as a high-safety alternative to phthalates, a class of chemicals regulators have restricted.

The substance turns up in everyday items across the United States and European Union:

• •soft plastic food packaging, including cling film
• •plastic wine corks
• •children's toys
• •medical devices
• •some textiles and flooring

What the study found

The New York University researchers examined the link between the DINCH plasticizer and birth weight using data on more than 6,600 pregnancies collected under the National Institutes of Health Environmental influences on Child Health Outcomes (Echo) Program.

Key findings from the Echo program study:

• •DINCH showed up in the urine of up to 70% of the women studied
• •higher exposure levels raised the risk of a child being classified as 'small for gestational age', below the 10th percentile for the pregnancy stage
• •each tenfold increase in exposure corresponded to a 27-gram drop in newborn birth weight, against an average newborn weight of about 3,400 grams, roughly 7.5lbs
• •Hispanic mothers and mothers with lower education levels were more likely to have children affected, the study found

First study of its kind

The paper is the first to link DINCH to lower birth weights and birth lengths. Fetal growth problems, the authors note, can raise the risk of heart disease, learning difficulties and obesity later in life.

Research into DINCH health risks remains scarce, though the work that exists points toward hormone-disrupting effects on children's development. Earlier studies on animals and human cells found DINCH by-products can interfere with the hormones that guide fetal development and may trigger inflammation affecting the delivery of nutrients and oxygen to the baby.

'Regrettable substitution' and the call for testing

After regulators moved against toxic phthalates such as DEHP in the 2000s, industry expanded DINCH use. The German chemical giant BASF is among its major producers, and global production volume jumped from 25,000 tons in 2002 to 400,000 tons in 2024.

The study's results, according to lead author Leonardo Trasande, raise serious concerns about a pattern known as regrettable substitution, in which a banned or restricted chemical is replaced by an alternative later found to carry its own risks. An example is Pfas chemicals like Pfoa being replaced with GenX compounds later found to be more toxic.

Trasande said the findings show the need for stronger oversight of chemicals in food packaging and household products, with testing required before market introduction. The Switzerland-based Food Packaging Forum, which has evidence that DINCH migrates from packaging into food, is concerned about the lack of health information and is conducting its own research on the substance.

According to Trasande, the UN plastics treaty now under negotiation offers a chance for better policies requiring chemicals to be tested before they are introduced to the market.