Collaborative ECHO research led by Leonardo Trasande, MD, MPP of NYU Langone Health investigates the potential connections between phthalates, their metabolites in the urine of pregnant individuals, and birth outcomes. This research, titled “Prenatal phthalate exposure and adverse birth outcomes in the USA: a prospective analysis of births and estimates of attributable burden and costs,” is published in The Lancet Planetary Health.
Phthalates are widely used chemicals found in some consumer products, and previous research has linked phthalate exposure to preterm birth. In response, the use of di-2-ethylhexyl phthalate (DEHP), a common type of phthalate, has decreased in recent years. However, there is limited research on the effects of the replacement phthalates, and the costs associated with phthalate exposure remain unquantified.
The study included 5,006 mother-child pairs from 13 ECHO Cohort Study Sites across the U.S. Researchers analyzed levels of 20 phthalate metabolites in urine samples collected at three different points during each participant’s pregnancy. Then, the team looked for associations between these metabolite levels and preterm birth. The team also investigated the differences between specific types of phthalates, comparing di-2-ethylhexyl phthalate (DEHP), a common type of phthalate, with several newer alternatives developed to replace it.
When the researchers grouped mothers based on the amount of DEHP metabolites (substances produced when the body breaks down DEHP) found in their urine, they found that the 10% with the highest levels had a 50% higher chance of giving birth before the 37th week of pregnancy compared to the 10% with the lowest levels.
Some common alternatives to DEHP were associated with an even higher risk of preterm birth. Women exposed to the highest amounts of these alternative chemicals—phthalic acid, di-isodecyl phthalate (DIDP), di-n-octyl phthalate (DnOP), and diisononyl phthalate (DiNP)—had twice the risk of preterm birth compared to those with little to no exposure to these alternatives. The team also calculated the costs associated with phthalate exposure.
“The number of premature births in the U.S. that could be linked to phthalate exposure in 2018 was between 24,000 and 120,000, potentially costing between $1.6 billion and $8.1 billion in medical expenses over the lifetime of the children,” Dr. Trasande said.
Future research could look at how exposure to replacement phthalates affects child development after birth. The European Union has prohibited the use of certain phthalates in some consumer products—as have California and a few other U.S. states.
Read the research summary here.