Phthalate exposure linked to preterm births: What are the risks?

Exposure to phthalates, a group of chemicals, during pregnancy, increases the chance of preterm births (babies born alive before 37 weeks of pregnancy are completed).

A recent study conducted by researchers at NYU Grossman School of Medicine has revealed a concerning connection between daily exposure to chemicals used in the production of plastic food containers and cosmetics and a significant number of preterm births in the United States.

WHAT ARE PHTHALATES?

Phthalates are a group of chemicals that are used to make plastics more durable.

The study estimates that nearly 56,600 preterm births in 2018 may be linked to these chemicals, known as phthalates, with associated lifetime medical costs ranging from $1.6 billion to $8.1 billion.

Phthalates have long been recognised for their interference with hormonal functions, impacting the body's essential processes.

According to the US Centers for Disease Control and Prevention, phthalates are in hundreds of products, such as vinyl flooring, lubricating oils, and personal-care products (soaps, shampoos, hair sprays).

RISKS OF EXPOSURE TO PHTHALATES

The exposure to these chemicals is believed to occur as consumer products are broken down and are ingested, raising health concerns such as obesity, cancer, and fertility issues.

The research, involving over 5,000 American mothers, ties phthalate exposure to an increased risk of lower weight and gestational age in newborns.

These risk factors can heighten the chances of infant death, impact academic performance, and potentially contribute to heart disease and diabetes.

PHTHALATES: A FINANCIAL BURDEN

Lead author of the study, Dr Leonardo Trasande, said that the significant medical and financial burden associated with preterm births is linked to phthalates.

"There is a clear opportunity here to lessen these risks by either using safer plastic materials or by reducing the use of plastic altogether whenever possible," said Dr Leonardo Trasande, Professor of Pediatrics in the Department of Pediatrics at NYU Langone Health.

Published in The Lancet Planetary Health on February 6, the study is considered the largest of its kind to date and includes a more diverse group of women than previous research on the topic.

The research utilised data from the Environmental Influences on Childhood Health Outcomes (ECHO) program, analysing various environmental, social, and economic factors that could influence children's health.

PHALATES LINKED TO HIGH RATES OF PRETERM BIRTHS

To assess prenatal phthalate exposure, researchers measured 20 different metabolites in urine samples collected at multiple points during each subject's pregnancy.

The study examined overall exposure and highlighted distinctions between specific phthalates, emphasising the need for regulating phthalates as a class.

Besides examining overall exposure to the toxins, the authors also searched for distinctions between specific phthalates.

In particular, they compared di-2-ethylhexyl phthalate (DEHP), a chemical long used to make plastic more flexible, with several newer replacements for DEHP, which has faced heightened scrutiny in recent years.

According to the findings, when grouping mothers based on the amount of DEHP metabolites in their urine, the 10% with the highest levels had a 50% increased risk of giving birth before week 37 of their pregnancy, compared with the 10% with the lowest levels.

Meanwhile, the risk for preterm birth was doubled for women exposed to the highest quantities of three common DEHP alternatives, di-isodecyl phthalate (DIDP), di-n-octyl phthalate (DnOP), and diisononyl phthalate (DiNP), compared with those who had little to no exposure.

MORE RESEARCH NEEDED

Dr Trasande now plans to expand the analysis to other countries and explore the health effects of preventing phthalate exposure.

While some states and European Union members have banned certain phthalate use in consumer products, Dr Trasande stressed the necessity for further research to understand the specific mechanisms linking phthalate exposure to preterm birth.