Higher prenatal exposure to a chemical increasingly used to replace phthalates was associated with differences in fetal growth, according to a recent ECHO Cohort study led by Leonardo Trasande, MD, MPP of NYU Langone Health.

Phthalates are widely used in food packaging, flooring, cosmetics, personal care products, and other everyday items. As manufacturers replace them with alternatives such as di(isononyl) cyclohexane-1,2-dicarboxylate (DINCH), researchers are working to understand whether these newer chemicals may also affect maternal and child health.

ECHO researchers analyzed data from 6,617 pregnancies at 22 ECHO Cohort Study Sites. They measured three DINCH breakdown products in urine collected during pregnancy and compared exposure levels with birth weight, birth length, pregnancy length, and infant size for gestational age.

Higher levels of DINCH-related markers were associated with lower birth weight and a greater likelihood of being born small for gestational age. Associations varied by infant sex: links with birth length were stronger among boys, while links with small-for-gestational-age status were stronger among girls. Third-trimester exposure appeared more strongly associated with lower birth weight for gestational age than exposure earlier in pregnancy.

Measurable DINCH markers were common among participants, suggesting widespread exposure in this population.

Because this was an observational study, the findings cannot show that DINCH directly caused these outcomes. Additional research may help clarify how DINCH affects pregnancy and fetal development and inform evaluations of other phthalate replacements.

This collaborative research, titled “Prenatal exposure to di(isononyl) cyclohexane-1,2-dicarboxylate and adverse birth outcomes in the USA: a prospective analysis of births in a large American birth cohort,” is published in Environment International.