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Part 2 of a 2-part series looking at environmental exposure to everyday chemicals and your health. For Part 1 click here.
If you are trying to conceive but are having a difficult time, what could be standing between you and a baby is your lifestyle and environment. A new Harvard University prospective cohort study is the first to find a possible association between parabens and impaired ovarian reserves.
The study, published in the August 2, 2013 edition of the peer-reviewed journal Environmental Health Perspectives, found that one common parabens type — propylparaben — impacts female fertility by lowering the number of viable oocytes in the ovaries or by possibly prematurely aging the ovaries.
“Typically, as a woman’s age increases, her ovarian reserve diminishes, which is referred to as 'ovarian aging' and is associated with reduced fertility,” the study stated.
“For women undergoing fertility treatments, ovarian aging is also associated with a decreased response to ovarian stimulation protocols and lower pregnancy success rates.”
Parabens are preservatives added by manufacturers to personal care, cosmetics and some foods to extend their shelf life.
In 2004, the Centers for Disease Control and Prevention, with the assistance of the U.S. Food and Drug Administration, documented widespread human exposure to parabens. Some experimental data has suggested that they act as estrogenic endocrine disruptors, leading some researchers to believe that there is an association between the chemicals and breast cancer.
The new study’s researchers, led by Russ Hauser, Frederick Lee Hisaw Professor of Reproductive Physiology at Harvard School of Public Health, measured paraben concentrations with markers of ovarian reserve in the urine of 192 women, aged 35 or older. The women were undergoing fertility treatment at Massachusetts General Hospital in Boston, between 2005-2010.
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.
About 18 billion pounds of phthalates are produced every year for products from adhesives to raincoats, garden hoses, and plastic bags to cosmetics, food containers and car interiors.
In several studies, phthalates have been associated with serious health problems such as infertility, testicular dysgenesis syndrome, obesity, asthma and allergies, as well as uterine fibroids and breast cancer, according to a 2010 review article.
Wood acknowledged these chemicals are everywhere so getting away from them completely is impossible. But said that some lifestyle changes and reading package labels can help.
He suggested that since evidence of health concerns are still emerging, as a precaution it would best if everyone were to follow the guidelines for safer toy, food and beverage consumer plastics.
Check the bottom of containers or plastic for the “recycle” code — those little circular arrow symbols that contain a number inside.
Safe plastics are labeled:
- 1 (PETE)
- 2 (HDPE)
- 4 (LDPE)
- 5 (PP)
Avoid plastics labeled:
- 3 (PVC or vinyl) as it may contain phthalates
- 6 (polystyrene foam)
- 7 (other)
Containers marked with a 7 may contain bisphenol A, also known as BPA, which can attack biological systems in very small doses.
If you'd like more information on plastics, a tip sheet is available for download online from the Pediatric Environmental Health Specialty Unit at http://www.aoec.org/PEHSU/documents/bpa_patient_july_8_08.pdf
Lynette Summerill is an award-winning writer and Scuba enthusiast who lives in San Diego with her husband and two beach loving dogs. In addition to writing about cancer-related issues for EmpowHER, her work has been seen in publications internationally.
Sources:
Urinary Paraben Concentrations and Ovarian Aging among Women from a Fertility Center. Kristen W. Smith, Irene Souter, Irene Dimitriadis, Shelley Ehrlich, Paige L. Williams, Antonia M. Calafat, and Russ Hauser. Environ Health Perspect; published early2 Aug. 2013. DOI:10.1289/ehp.1205350.
Abstract at: http://ehp.niehs.nih.gov/1205350
Toxic Effects of the Easily Avoidable Phthalates and Parabens. Walter J. Crinnion, ND. Alternative Medical Review, Vol.15 No.3, 2010.
Abstract with link to full text at: http://www.ncbi.nlm.nih.gov/pubmed/21155623
Interview Samuel Wood, 15 Aug. 2013
Testicular dysgenesis syndrome: an increasingly common developmental disorder with environmental aspects. N.E. Skallebaek, E. Raipert-De Meyts, K.M. Main. Hum Reprod. 2001 May; 16)5):972-8.
Abstract with link to full text at: http://www.ncbi.nlm.nih.gov/pubmed/11331648
Reviewed September 3, 2013
by Michele Blacksberg RN
Edited by Jody Smith
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