Exposure to Chemicals in Plastic Products May Impact Male Fertility for Generations: Study

Prenatal exposure to chemicals commonly found in plastic products, known as phthalates, may negatively affect the fertility for multiple generations of men, according to the findings of a new study conducted on mice. 

Researchers with The Endocrine Society indicate that exposure to endocrine disrupting chemicals during pregnancy may reduce the son, grandson, and great-grandson’s fertility, even when the second and third generation mothers are not exposed. The findings were presented March 19, at ENDO 2018, the 100th annual meeting of the Endocrine Society, and are considered preliminary until published in a peer-reviewed journal.

The study evaluated the effect of di-(2-ethylhexyl) phthalate (DEHP) on pregnant mice and their offspring for two generations. DEHP is one of most widely used endocrine disrupting chemicals, and is found in many consumer products, including cosmetics, detergents, food packaging, plastic toys, pill coatings, medical devices, as well as PVC piping and tubing.

Past research into endocrine disrupters has indicated widespread negative effects, including increased risk of allergies in offspring of exposed women and increased risk of obesity and diabetes later in life.

The findings of the new study indicated exposure to DEHP not only reduced the amount and quality of the sperm of the son whose mother was exposed, but also to future generations of offspring.

Researchers gave DEHP to some pregnant mice and corn oil as a control in others, in four doses; from 11 days after they conceived until birth.

Adult males born to the female mice exposed during pregnancy were bred with unexposed females to produce a second generation. Then, young adult males from the second generation were bred with unexposed females to produce a third generation.

Levels of sex hormones, sperm concentrations, and sperm motility were measured at 15 months in each generation.

Sons in the second generation born from mother’s who were given the highest levels of DEHP had abnormal reproductive results. They had lower testosterone concentrations, lower sperm counts and decreased sperm motility.

According to a similar study published in 2014, exposure to phthalates led to lower levels of testosterone in men, women, and children.

Sons in the third generation born from mothers in the highest DEHP exposure group also exhibited reproductive abnormalities. However, those from that same generation  who were given the lowest doses of DEHP experienced the greatest amount of reproductive abnormalities.

Overall, mice prenatally exposed to DEHP had less testosterone in their blood and lower sperm counts. They also became infertile at much earlier ages than when fertility first typically begins to decreased.

Sperm counts among human men have dropped significantly over the last few decades. Many researchers blame this and other widespread hormonal effects on the increase in phthalate exposure, leading some researchers to call for a reduction in the exposure to these and other endocrine disrupting chemicals.