Common Chemical in Consumer Goods Tied to Early Birth

Phthalates exposure in pregnant women linked to preterm birth

/ Author:  / Reviewed by: Joseph V. Madia, MD Beth Bolt, RPh

(RxWiki News) Being born too early is a leading cause of death among newborns. So, understanding the causes of preemie births may help doctors prevent more of them.

A recent study found that higher amounts of certain phthalates in a pregnant women's blood appeared to affect her risk of preterm labor.

Phthalates are chemicals found in a wide range of consumer goods, including lotions, perfumes and deodorants.

The three phthalates found to be related to preterm birth go by the initials MEHP, MECPP and DEHP.

The more evidence there was of these three phthalates in the women's urine, the more likely it was that they would give birth earlier than they would go full term.

"Look for alternatives to products with phthalates."

This study, led by Kelly K. Ferguson, MPH, of the Department of Environmental Health Sciences at the University of Michigan School of Public Health in Ann Arbor, looked for links between preterm birth and a woman's exposure to phthalates.

The researchers compared two groups of women who were already participating in a different, larger study together in Boston, Massachusetts.

One group of 130 women had given birth to their babies early (before 37 weeks of pregnancy) while the other 352 women had given birth to their babies at full term.

The researchers tested these women's urine samples up to three times during their pregnancies for the levels of nine different phthalates found in them.

There are a wide range of phthalates that exist, each with relatively long chemical names and known by abbreviations.

Four of these were found in higher amounts in the urine of women who had preterm babies than in the urine of women who gave birth at term.

These four phthalates were the following:

  • di-2-ethylhexyl phthalate (DEHP)
  • mono-(2-ethyl)-hexyl phthalate (MEHP)
  • mono-(2-ethyl-5-carboxypentyl) phthalate (MECPP)
  • mono-n-butyl phthalate (MBP)

The researchers then adjusted their analysis to account for other risk factors that might have independently increased the risk for preterm birth in the women.

However, there still appeared to be an increased risk for preterm birth among women exposed to higher levels of three phthalates in particular.

Women had 33 to 40 percent higher odds of having a preterm baby if they had the highest levels of MEHP, MECPP and DEHP in their urine.

There was a similar pattern seen for MBP, but it's possible these findings were related to chance, and the risk was lower — only about 27 percent higher odds of preterm birth.

"Our results demonstrate a robust increase in the odds of preterm birth in association with urinary phthalate metabolite concentrations during pregnancy," the researchers wrote.

"Specifically, [mothers'] levels of DEHP metabolites, including MEHP (the putative toxic metabolite of DEHP), MECPP (the most stable marker of DEHP exposure), and summed DEHP metabolites, showed the strongest and most clearly dose-dependent relationships with odds of birth before 37 weeks’ gestation."

This last statement means that the link between preterm birth and exposure to those chemicals became stronger the more evidence there was of exposure to those phthalates in the women's urine.

This study was published November 18 in the journal JAMA Pediatrics. The research was funded by the National Institute of Environmental Health Sciences. The authors reported no conflicts of interest.

Review Date: 
November 18, 2013
Last Updated:
November 25, 2013