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An excerpt from Chapter 4, Hormone Havoc
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As we pursue the mystery of hand-me-down poisons, two tragic episodes in medical history contain important lessons and immediate relevance to our quest. They leave no doubt that humans are vulnerable to hormone-disrupting synthetic chemicals and demonstrate that animal studies had repeatedly provided an early warning about the hazards for humans. From the very beginning, these warnings were clear and ominous. As early as the 1930s, researchers at Northwestern University Medical School showed that tinkering with hormone levels during pregnancy was dangerous business, particularly for the fetus undergoing rapid development in the womb. In some of the experiments, the researchers simply gave an extra dose of estrogen to pregnant rats, who already have this female hormone in their bodies. Nevertheless, the impact on their pups proved dramatic. At birth, the rat offspring showed striking abnormalities stemming from disrupted sexual development. The female pups exposed to extra natural or synthetic estrogen in the womb suffered structural defects of the uterus, vagina, and ovaries; males had stunted penises and other genital deformities. In contrast to Fred vom Saal's work, which explores the effect of tiny natural variations in hormone levels in the womb, these earlier experiments boosted a female's hormone levels beyond the normal range by adding estrogen from outside the body. They showed that larger shifts in hormone levels scrambled the chemical messages and derailed sexual development. Although estrogen at normal levels is essential for development, too much of it can wreak havoc. This cautionary evidence was timely indeed. In 1938, British scientist and physician Edward Charles Dodds and his colleagues had announced the synthesis of a chemical that somehow acted in the body like natural estrogen and the medical community was abuzz with excitement. Leading researchers and gynecologists hailed the man-made estrogen, known as diethylstilbestrol or DES, as a wonder drug with a host of potential uses. Almost immediately, researchers began giving DES to women experiencing problems during pregnancy in the belief that insufficient estrogen levels caused miscarriages and premature births. What would prove to be a massive human experiment -one that eventually involved an estimated five million pregnant women in the U.S., Europe, Latin America and elsewhere-was just getting under way. In the decades that followed, doctors not only prescribed DES to prevent miscarriages, they began to recommend it for untroubled pregnancies as if it were a vitamin that could improve on nature. Prestigious publications, among them the Journal of Obstetrics and Gynecology, carried drug company ads such as one from Grant Chemical Company that appeared in June 1957, which touted the use of DES for "ALL pregnancies," boasting that it produced "bigger and stronger babies." DES also found a broad market beyond pregnant women. Doctors used it liberally to suppress milk production after childbirth, to alleviate hot flashes and other menopausal symptoms, and to treat acne, prostate cancer, gonorrhea in children, and even to stunt the growth in teenage girls who were becoming unfashionably tall. For years, college clinics doled out DES as a "morning after" contraceptive. Farmers were equally bullish on DES and used tons of it as an additive to animal feed or in neck or ear implants because it speeded the fattening of chickens, cows, and other livestock. The postwar era was a time of Promethean optimism, when everyone from physicians to farmers rushed to embrace new "miracle" technologies. DES was just one of many new synthetic chemicals that promised to give us control over the forces of nature. With a mixture of hubris and naiveté, advocates of progress imagined a world with unlimited potential for the mastery of life itself.
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