Cosmetic chemicals can cause preterm births and precocious puberty, researchers find

13 Jul 2022 --- A study by the National Institutes of Health (NIH) suggests that prenatal phthalate exposure is associated with preterm birth. Researchers from Spain also studied the impact of exposure to phthalates during early life on reproductive development and function and found that it influences the timing of pubertal development.

Phthalates are synthetic compounds, often called plasticizers, used in common consumer goods including personal care products, food processing and packaging.

Household dust, one’s diet and the use of certain cosmetics are just some potential causes of exposure. As a result, pregnant women are frequently exposed to phthalates.

Prenatal phthalate exposure is associated with preterm birth, a study finds.Problematic pregnancies
Preterm birth is when a mother delivers a baby three or more weeks before her expected due date. During these final few weeks of pregnancy, the lungs are still maturing, and the fetus begins to position itself head down.

Premature newborns may experience greater health issues both at delivery and later in life than babies delivered at full-term. Intellectual and developmental difficulties in the long term, as well as issues with their lungs, brain, eyes and other organs, can affect prematurely born babies.

A study conducted by the NIH has investigated the prospective association between urinary biomarkers of phthalates in pregnancy and preterm birth among individuals living in the US.

During pregnancy, participants gave urine samples for the measurement of phthalate monoester metabolites: this is the chosen biomarker of phthalate exposure. Concentrations of 11 phthalate metabolites were standardized for testing, and mean repeated measurements across pregnancy were calculated.

The researchers found that women with higher concentrations of several phthalate metabolites in their urine were more likely to deliver their babies preterm. Urinary biomarkers of common phthalates used in consumer products were a risk to delivering preterm as well.

Pubertal progress
Various Spanish institutions such as the Instituto de Investigación Biosanitaria de Granada, the University of Granada and the Spanish Consortium for Research on Epidemiology and Public Health, carried out the study on early puberty. 

Phthalate exposure has been associated with reduced anogenital distance, urogenital malformations, poorer sperm quality and reduced testosterone levels in men. Children exposed to prenatal phthalates could have premature pubertal development.

Moreover, placental dysfunction, adverse pregnancy outcomes (preterm delivery, low birth weight), ovarian insufficiency, endometriosis, hormone imbalance and infertility in women have been recognized as a result of phthalate exposure.

Meanwhile, children with early puberty are at higher risk for behavioral disorders and psychosocial difficulties during adolescence, early sexual debut, accelerated skeletal maturation and short adult height, obesity, type 2 diabetes, cardiovascular disease and endocrine-related cancers such as breast and testicular cancer in later life.

In the study conducted by researchers in Spain, the association of prenatal phthalate exposure with pubertal development in boys and girls was investigated.

Researchers accordingly found that pregnant women exposed to certain phthalates birthed babies with pubertal development at age 7–10 years, especially earlier puberty in boys with normal weight and overweight girls. 

Their results suggest that childhood obesity may be an effect modifier in the association between prenatal phthalate exposure and puberty development. 

Household dust, diet, and the use of certain cosmetics are potential causes of exposure.However, there was no clear evidence of the effect of the phthalate mixture on advancing or delaying puberty in boys or girls, suggesting that other factors in childhood could be more important than prenatal exposure.

Preventing phthalate exposure

Both studies provide additional evidence of the need to reduce phthalate exposures among pregnant individuals, which could take the form of either behavioral interventions or regulations. 

Although exposure to phthalates can come from a variety of contexts and sources, there has been a long-running research endeavor to precisely identify if a single source accounts for the bulk of human exposure.

The US Consumer Product Safety Commission made an effort to quantify exposure by source and discovered that, rather than the prejudiced children's toys, the main exposure sources were actually food and medication. Unfortunately, there is still a lot of doubt surrounding the main exposure source.

Targeted interventions, such as changing the kind of personal care goods that are bought, might aid in changing consumer habits that result in phthalate exposure.

Alternately, dietary strategies to lower exposure have shown conflicting outcomes. Economic inequality may make it harder for some communities to acquire phthalate-free goods and food choices, and this simply aids the challenge of avoidance.

The research results are consistent with the hypothesis that modest but potentially feasible, reductions in phthalate exposure could reduce rates of preterm birth and precocious puberty. These findings highlight the need for public health and policy measures to reduce phthalate exposures among pregnant individuals.

By Mieke Meintjes