FPESA Research Paper Assessment: The Pill May Reduce Estrogen Pollution

FPESA Research Paper Assessment: The Pill May Reduce Estrogen Pollution

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Usman Khan and Jim A. Nicell, “Contraceptive Options and Their Associated Estrogenic Environmental Loads: Relationships and Trade-Offs,” PLoS ONE, vol. 9, no. 3 (March 2014), e-page: e92630. DOI: 10.1371/journal.pone.0092630. URL (full paper): www.plosone.org/article/fetchObject.action?uri=info:doi/10.1371/journal.pone.0092630&representation=PDF. This paper was collaboratively assessed.

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Much as it may seem to defy logic, the use of estrogen-based birth control pills ultimately reduces estrogen pollution into the environment.

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Much as it may seem to defy logic, the use of estrogen-based birth control pills ultimately reduces estrogen pollution into the environment, at least in the United States, these authors conclude. Their analysis weighs multiple sources of environmental estrogen associated with human reproduction and its control. It applies the controversial concept of parents’ environmental “legacy” embodied in the impact that their children and descendants will have on the environment, as originally described and calculated for heat-trapping carbon dioxide emissions in a paper by Murtaugh and Schlax (which the FPESA project also will be annotating). Khan and Nicell take into account the savings, accrued by reductions in unintended pregnancy and unwanted births as a result of the use of family planning, in future estrogen secretion that otherwise would occur in later generations. Contraception also reduces pregnancies and births that otherwise would make their own near-term contributions of natural estrogens.

Khan and Nicell calculate that discontinuing the use of the most common type of oral contraceptive would multiply estrogen pollution by a factor of 1.7. They conclude that “13 percent of the net annual estrogenic load to the environment can be averted by fully meeting the contraceptive needs of the population of the U.S.A.”

The datasets used for the authors’ calculations are included in 15 supplementary documents, all available online, and contain useful and easy-to-understand information on the failure rates of different contraceptive methods in the United States as well as the incidents of unintended pregnancy and mistimed and unwanted births.

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A significant fraction of the estrogenic mass released to environment can be averted by improving the level with which their contraceptive needs are met.

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Key quote: “[W]hile the issue of estrogen impacts on the environment cannot be addressed solely by meeting the population’s contraceptive needs, a significant fraction of the estrogenic mass released to environment can be averted by improving the level with which their contraceptive needs are met.”

FPESA assessments (eight total) were mostly enthusiastic about the strength of and imaginative reach of this paper. One assessor called it “fascinating,” while another commended its “easy reading.” A few assessments were less impressed, questioning how dependable the data were and whether the findings were applicable outside the United States. (The paper makes clear that the findings are limited to the United States. The researchers believe their methodology is applicable elsewhere, along with their key finding: that eliminating estrogen-based contraception would not solve the problem of estrogen pollution.) One assessor noted a key problem with assessing environmental legacies: How can one know enough about the distant future to know how long a line of descendants will last, and what their environmental behavior will be? Khan and Nicell acknowledged such limitations and offered their conclusions as an initial calculation relating to a question not previously examined.

Overall assessment: While estrogen pollution itself is at best a minor component of environmental sustainability, the paper is especially relevant to the FPESA project in using rich data to test empirically a hypothesis on the impact of family planning directly on an environmental problem. (Although not addressed in this paper, other research has linked estrogen pollution in U.S. waterways to the feminization of aquatic life and potentially to human health effects.) Estrogen pollution comes not just from the use of estrogen-based contraceptives, but also from natural excretions, which are themselves reduced, now and in the future, by the use of birth control.

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Estrogen pollution comes not just from the use of estrogen-based contraceptives, but also from natural excretions, which are themselves reduced, now and in the future, by the use of birth control.

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The originality of the research question and methodology strengthen the value of this paper. So does the authors’ calculation of the estrogenic legacy effect of oral contraceptive use. The calculation itself is questionable, requiring assumptions about fertility far into the future. Yet if slowing population growth reduces environmental impacts in the short and medium term, then lasting benefits will be likely as the demographic impact of slower growth is amplified in successive generations. The legacy effect deserves (but only rarely receives) investigation and discussion.

 

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The following annotation and assessment is excerpted from the forthcoming report of the Family Planning and Environmental Sustainability Assessment (FPESA) project. The report will contain selected annotations from more than 930 peer-reviewed articles reviewed for potential relevance to the hypothesis that family planning supports environmental sustainability. The annotations are written by project director Robert Engelman with input from members of the project team and, where indicated, members of the project’s international network of research assessors.   

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