Reproductive Health and Fertility Problems
In the U.S. today, there is increasing concern that environmental contaminants may be harming the reproductive health and fertility of women and men. Reproductive and fertility problems appear to be on the rise:
In women:
- At least 12% of women reported difficulty in conceiving and maintaining pregnancy in 2002, an increase of 40% from 1982. The rate has almost doubled in younger women, ages 18–25. (Anjani Chandra and Elizabeth Hervey Stephen, “Impaired Fecundity in the United States: 1982-1995,” Family Planning Perspectives, 30, no. 1 (1998): 34–42.) (Anjani Chandra, et al., “Fertility, Family Planning and Reproductive Health of US Women: Data from the 2002 National Survey of Family Growth,” National Center for Health Statistics, Vital Health Statistics, 23, no. 25 (2005).)
- Uterine fibroids are the number one cause of hysterectomy in reproductiveaged women, accounting for more than 200,000 of these surgeries annually in the U.S. alone. In addition, uterine fibroids are a significant cause of pelvic pain, heavy menstrual bleeding, abnormal uterine bleeding, infertility, and pregnancy complications.
- Fibroids and other fertility-related diseases, like endometriosis and polycystic ovarian syndrome, are diagnosed more frequently now, which may result from a true increase, better detection, or both.
In men:
- According to a large study of men from the Boston area, testosterone levels in adult men are declining. This decline is not explained by an increase in age or other health or lifestyle factors such as obesity or smoking. (Thomas G. Travison, et al., ”A Population-Level Decline in Serum Testosterone Levels in American Men.” The Journal of Clinical Endocrinology & Metabolism, 92, no. 1 (2007).)
- Testicular cancer increased by 60% between 1973 and 2003 in the U.S. (Mona Shah, et al., “Trends in Testicular Germ Cell Tumours by Ethnic Group in the United States,” International Journal of Andrology, 30 (2007): 206–13.)
- There have been significant declines in sperm counts in men in the U.S., Europe, and Australia. (Shanna Swan, Eric P. Elkin, and Laura Fenster, “The Question of Declining Sperm Density Revisited: An Analysis of 101 Studies Published 1934–1996,” Environmental Health Perspectives, 108, no. 10 (October 2000): 961–66.)
In children:
- Reproductive tract abnormalities are increasing in certain populations. Cryptorchidism (undescended testicles) increased 200% between 1970 and 1993. (Leonard J. Paulozzi, J. David Erickson, and Richard J. Jackson, “Hypospadias Trends in Two US Surveillance Systems,” Pediatrics, 100, no. 5 (November 1997): 831–34.)
- On average, babies are now born one week earlier than they were 15 years ago. And 30% more babies are born prematurely—the major reason more babies are being born with low birth weight. (M. Davidoff, et al., “Changes in the Gestational Age Distribution among U.S. Singleton Births: Impact on Rates of Late Preterm Birth, 1992 to 2002,” Seminars in Perinatology, 30, no. 1 (2006): 8–15.) (See Figure 2).
- There is evidence of a trend in the U.S. toward earlier breast development and onset of menstruation in girls. A weight-of-the-evidence evaluation of human and animal studies suggests that endocrine-disrupting chemicals, particularly estrogen mimics and antiandrogens, as well as increased body fat, are important factors associated with altered puberty timing. (Susan W. Euling, et al., ”Role of Environmental Factors in the Timing of Puberty.” Pediatrics, 121, S3 (February 2008): S167-71.)
Figure 2 - Percent of Preterm Births by Year, 1994-2004
Taken from the report, Reproductive Roulette, published by the Center for American Progress, 2009
Source: TJ. Mathews and Marian F. MacDorman, Infant Mortality Statistics from the 2003 Period Linked Birth/Infant Death Data Set, National Vital Statistics Reports 54 (16) (May 2006) Robert L. Goldenberg and Dwight J. Rouse, “Prevention of Premature Birth,” New England Journal of Medicine 339 (5) (1998): 313–20; Bernard Weiss and David C.Bellinger, “Social Ecology of Children’s Vulnerability to Environmental Pollutants, Environmental Health Perspectives 114 (10) (2006): 1449–85
Health care costs
In 2002, U.S. patients and their insurers spent an estimated $2.9 billion on infertility treatments. (The Collaborative on Health and the Environment, Vallombrosa Consensus Statement on Environmental Contaminants and Human Fertility Compromise October 2005, http://www.healthandenvironment.org/infertility/vallombrosa_documents (accessed September 28, 1009).) Hysterectomies for uterine fibroids cost Americans $1.7 billion per year.
In 2005, preterm birth cost the U.S. at least $26.2 billion, or $51,600 for every infant born prematurely. The costs broke down as follows:
- $16.9 billion (65%) for medical care
- $1.9 billion (7%) for maternal delivery
- $611 million (2%) for early intervention services
- $1.1. billion (4%) for special education services
- $5.7 billion (22%) for lost household and labor market productivity (Richard E. Behrman and Adrienne Stith Butler, ed, “Committee on Understanding Premature Birth and Assuring Healthy Outcomes,” Preterm Birth: Causes, Consequences and Prevention, (Washington, DC, Institute of Medicine of National Academies, 2006).)
The average first-year medical costs, including both inpatient and outpatient care, were about 10 times greater for preterm infants ($32,325) than for full-term infants ($3,325).
The link to chemical exposure
The Centers for Disease Control and Prevention (CDC) has published data showing that exposures to chemicals like phthalates, bisphenol A (BPA), perfluorinated compounds, and cadmium are common. The CDC reports that almost everyone has these chemicals in their bodies—some at levels near or above those shown in scientific studies to cause adverse effects on reproductive health.
Over the past decade, a wealth of new studies has shown how some chemicals can act as endocrine disruptors—chemicals that interfere with normal hormone function and regulation. Among these are animal studies that link prenatal and early-life exposures to BPA found in polycarbonate plastic and food can linings to permanent reproductive changes and increased risks of later reproductive health problems, such as infertility, early puberty, breast cancer, and prostate cancer.
In laboratory animals, including nonhuman primates, BPA has previously been identified to affect development of the brain, causing changes in gender specific behaviors. Recently, a new human study reported that the higher a pregnant woman’s BPA levels were during her first 16 weeks of pregnancy, the more likely her child was to later show behavior somewhat atypical of its gender at age two. Girls engaged in more masculinized behaviors, while boys were more feminized. (Jo M. Braun, et al., “Prenatal Bisphenol A Exposure and Early Childhood Behavior,” Environmental Health Perspectives-in-press (2009).) Another new study of Chinese men exposed to higher levels of BPA in their workplace suggests that BPA can harm the reproductive health of adults as well. The report found substantially more sexual dysfunction among the exposed workers than a control group, including four times more erectile dysfunction and seven times more difficulty ejaculating. (D. Li, et al., Occupational Exposure to Bisphenol-A (BPA) and the Risk of Self-Reported Male Sexual Dysfunction, Human Reproduction, published on-line 2009 Nov 10. [Epub ahead of print])
A wide range of wildlife populations has been adversely affected by exposure to endocrine-disrupting contaminants. Impacts among birds, fish, shellfish, mammals, and reptiles include decreased fertility and increased reproductive tract abnormalities; feminization and demasculinization in the males; and masculinization and defeminization in the females. (Tracey J. Woodruff, et al., “Proceedings of the Summit on Environmental Challenges to Reproductive Health and Fertility: Executive Summary.” Fertil Steril, 89, no. 2 (February 2008): 281–300)
Prenatal exposure to phthalates found in personal care products and in items made from vinyl has been linked to birth defects of the male reproductive system and feminized behaviors in boys. Some researchers now group the male birth defects—undescended testes (cryptorchidism) and deformities of the penis (hypospadias)—with two other conditions of the male reproductive tract, low sperm counts and testicular cancer. These four medical conditions are collectively called testicular dysgenesis syndrome (TDS). Animal studies suggest that a TDS-like condition can be observed after fetal exposure to phthalates. (E. Diamanti-Kandarakis, et al. “Endocrine-Disrupting Chemicals: An Endocrine Society Scientific Statement,” Endocrine Reviews, 30, no. 4 (2009): 293–342.)
In November 2009, a new study of mothers and their children found that boys born to mothers with higher levels of phthalates in their urine during pregnancy were more likely to exhibit feminized behaviors than boys whose mothers had lower levels of exposure. (SH Swan et al., “Prenatal phthalate exposure and reduced masculine play in boys.” International Journal of Andrology, (November 16, 2009) [Epub ahead of print]) Two other studies have also suggested that phthalate levels in young girls are linked to early breast development. (Ivelisse Colón, et al., “Identification of Phthalate Esters in the Serum of Young Puerto Rican Girls with Premature Breast Development.” Environmental Health Perspectives, 108, no. 9 (2000): 895–900.) (L. Qiao, L. Zheng, D. Cai,[Study on the Di-N-Butyl Phthalate and Di-2-Ethylhexyl Phthalate Level of Girl Serum Related with Precocious Puberty in Shanghai],Wei Sheng Yan Jiu, 36 (2007): 93–95.)
Low levels of prenatal exposure to perfluorinated chemicals, commonly used in stain-proof and stick-free products, were tied to low birth weight and body mass in newborns born at a city hospital in Baltimore. Babies with higher levels of these compounds tended to be slightly but significantly smaller than those with lower exposure. (Benjamin J. Apelberg, Frank R. Witter, Julie B. Herbstman, et al., “Cord Serum Concentrations of Perfluorooctane Sulfonate (PFOS) and Perfluorooctanoate (PFOA) in Relation to Weight and Size at birth,” Environmental Health Perspectives, 115, no. 11 (November 2007): 1670-6.) A recent study found that Danish men with higher levels of perfluorinated compounds had fewer normal sperm and lower sperm concentrations. (Ulla Nordström Joensen, et al., “Do Perfluoroalkyl Compounds Impair Human Semen Quality?” Environmental Health Perspectives, 177, no. 6 (June 2009).) Cadmium, a metal used in batteries, pigments, metal coatings, and plastics, has been linked to reduced sperm motility and to gynecological disorders such as endometriosis. (Tracey J. Woodruff, et al., “Proceedings of the Summit on Environmental Challenges to Reproductive Health and Fertility: Executive Summary.” Fertil Steril, 89, no. 2 (February 2008): 281–300.)
Reproductive health, fertility and TSCA
In June 2009, The Endocrine Society, a professional association devoted to research on hormones and the clinical practice of endocrinology, issued a scientific statement on endocrine disrupting chemicals which found: (Ibid.)
The evidence for adverse reproductive outcomes (infertility, cancers, malformations) from exposure to endocrine disrupting chemicals is strong, and there is mounting evidence for effects on other endocrine systems, including thyroid, neuroendocrine, obesity and metabolism, and insulin and glucose homeostasis.
Among the statement’s recommendations for the future is this suggestion:
As endocrinologists, we suggest that The Endocrine Society actively engages in lobbying for regulation seeking to decrease human exposure to the many endocrine-disrupting agents.
In November 2009, the American Medical Association (AMA) House of Delegates passed a resolution introduced by The Endocrine Society that calls for the AMA to work with the federal government to enact new federal policies to decrease the public’s exposure to endocrine-disrupting chemicals.
These “new federal policies” and “regulation to decrease human exposure” would come through effective reform of TSCA. No chemicals are currently regulated under TSCA because of their potential to harm reproduction or development. But other authoritative bodies have listed more than 50 industrial chemicals as reproductive toxins. (California Environmental Protection Agency, “Proposition 65: The Safe Drinking Water and Toxic Enforcement Act of 1986,” Chemicals Known to the State to Cause Cancer or Reproductive Toxicity List as of September 11, 2009.) TSCA reform should prioritize action on these chemicals and others such as bisphenol A, phthalates, and perfluorinated chemicals, which have been identified as harmful to reproduction and development. (This entire section is informed by the article “Female Reproductive Disorders: the Roles of Endocrine-Disrupting Compounds and Developmental Timing,” by D. Andrew Crain, et al., Fertility and Sterility, 90, no. 4 (2008): 911-40.)
