Prenatal exposure to chemicals called phthalates, that are utilized in a whole lot of products, may result in hormonal changes in females that might affect their future fertility, suggests a study in mice being presented Thursday at ENDO 2023, the Endocrine Society’s annual meeting in Chicago, Sick.

The study found female mouse embryos exposed to phthalates during gestation had lower testosterone levels than those not exposed to the chemicals. Immediately after birth, female mice exposed to phthalates during gestation had lower levels of the hormone estradiol than those not exposed.

These changes in hormone levels occurred during critical times of their development and will eventually result in greater problems with fertility.”

Mary Bunnell, Lead Researcher, University of Illinois Urbana-Champaign in Urbana, Sick

Through the middle of gestation and through the period right after birth, the body develops and changes significantly. At these times, elevated sex hormones are crucial for correct reproductive development and performance. In males, the first sex hormone is testosterone, which is related to penile and testicular growth and the masculinization of neurons. In females, the first sex hormone is estradiol, which stimulates breast tissue and acts as a growth hormone for the reproductive organs. The rise in levels of those hormones allows for the maturation of the sexual organs and creates the premise for future fertility.

“The extent of sex hormones through the fetal and neonatal periods are critical, and disruptions in the degrees at these times may cause reproductive abnormalities that might not be evident until maturity,” Bunnell said.

Endocrine-disrupting chemicals reminiscent of phthalates are ubiquitous in the environment, so it is incredibly difficult to avoid exposure. In keeping with the U.S. Food and Drug Administration, phthalates are utilized in the manufacture of toys, vinyl flooring and wall covering, detergents, lubricating oils, food packaging, pharmaceuticals, blood bags and tubing, and private care products, reminiscent of nail polish, hair sprays, aftershave lotions, soaps, shampoos and perfumes. They will leach from packaging and into the food we eat.

Ongoing research has revealed many health concerns linked with phthalate exposure, particularly of the reproductive system and other endocrine systems. Prepubescent children are especially in danger. It has been shown that phthalates can cross the placenta, putting the developing fetus susceptible to gestational exposure to those dangerous chemicals during a sensitive period of development, Bunnell said.

In the brand new study, researchers studied two groups of mice. In a single group, the researchers mimicked human exposure to phthalates by orally dosing pregnant mice with a phthalate mixture formulated to reflect the degrees of phthalates present in humans. Within the second group, pregnant mice weren’t exposed to phthalates. They measured fetal and newborn hormones of the offspring in each groups.

During gestation, female embryos exposed to phthalates had lower testosterone levels than non-exposed females. Female newborns had lower estradiol than non-exposed females. Nevertheless, they didn’t find such changes in males. The outcomes show that prenatal phthalate exposure had sex-dependent effects on hormonal levels at critical times of development. Follow-up study indicates that those sex-dependent hormonal changes aren’t because of the impact on gonadal sex steroid production in women and men, but a sex-dependent impact on the liver’s metabolic capability.

“This study initiates a brand new perspective on the reproductive toxicity of phthalates, placing the liver as the first goal,” Bunnell said. “It provides a singular approach to understanding sex-dependent effects of endocrine-disrupting chemicals, and it could pave the best way for the event of clinical strategies to mitigate the results of phthalate exposure.”

Bunnell is scheduled to present on the Society’s ENDO 2023 endocrine-disrupting chemicals news conference at 10 AM Central on Saturday, June 17.