For the study, the researchers wanted to know if exposure to parabens is associated with diminished ovarian reserve among women undergoing in vitro fertilization (IVF) or intrauterine insemination (IUI).
To test this assumption they measured day 3 follicle stimulating hormone (FSH), antral follicle count (AFC), and ovarian volume (OV) in each of the women’s urine, as well as concentrations of three common parabens, methylparaben (MP), propylparaben (PP), and butylparben (BP).
Higher day 3 FSH levels and a lower AFC and OV generally indicate a diminished ovarian reserve, according to the study. Besides a woman’s age, “other factors such as exposure to endocrine disrupting chemicals can possibly diminish ovarian reserves,” the study said.
The researchers found parabens concentrations in the women’s urine samples similar to those in the general population. MP and PP were detected in greater than 99 percent of samples, and BP in greater than 75 percent.
But it was propylparaben that caught the researchers’ attention. The higher the PP concentration, the higher day 3 FSH and lower AFC, leading researchers to conclude that exposure to this paraben type may adversely affect ovarian reserve, and thus contribute to premature ovarian aging.
“The Harvard study is where the rubber meet the road,” said Dr. Samuel Wood, reproductive endocrinologist specializing in infertility and a faculty member at University of California, San Diego. Wood was not associated with the study.
“It took a study like this to get serious [within the scientific and medical community] about chemicals being added to products we buy. The outcome of this study isn’t subtle. The current implantation failure rate is over half, so this is serious business.”
Wood counsels his patients to avoid parabens and phthalates plasticizers as much as possible for at least six months prior to trying to conceive.
Phthalates are a group of chemicals added to consumer products to provide flexibility and resilience, Di-ethylhexyl phthalate (DEHP) being the most common.