Side Effects of Diethylstilbestrol

Diethylstilbestrol is an artificial form of nonsteroidal estrogen that was initially synthesized in 1938 and used to prevent complications in pregnancy. The National Cancer Institute reports that use of diethylstilbestrol declined in the 1950s because it was not found to be effective, and overall use ceased in 1971 when it was discovered that it could hinder reproductive development in fetuses during the first five months of pregnancy. Because diethylstilbestrol is now considered a carcinogen by the National Toxicology Program, it is no longer manufactured in the United States.

Clear-Cell Adenocarcinoma

• The National Toxicology Program (NTP) of the U.S. Department of Health and Human Services reports in the Eleventh Edition of its Report on Carcinogens that diethylstilbestrol is a human carcinogen. More specifically, diethylstilbestrol has been proven to cause clear-cell adenocarcinoma, a cancer in the vagina and cervix. This form of cancer has been prevalent to women who have become known as "diethylstilbestrol daughters" whose mothers were treated with the drug during pregnancy.

Testicular Cancer

• The NTP's Report on Carcinogens also identifies diethylstilbestrol as a cause of testicular cancer in men whose mothers were treated with the drug during pregnancy. Likewise, men who developed the disease through this means have come to be known as "diethylstilbestrol sons."

Breast Cancer

• The NTP's Report on Carcinogens reports that the mothers themselves who were treated with high doses of diethylstilbestrol were at greater risk of developing breast cancer. However, the report also states that findings about breast cancer risk for "diethylstilbestrol daughters" is inconclusive.

Hypospadias

• A 2002 study by the Netherlands Cancer Institute in Amsterdam titled "Hypospadias in Sons of Women Exposed to Diethylstilbestrol in Utero" concluded that there was an increased risk in males of hypospadias (a condition in which the urethra opens beneath the skin of the penis) in sons whose mothers were exposed in utero to diethylstilbestrol during their pregnancy.

Abdominal Cryptorchidism

• A 2009 study by the Zhongnan Hospital Department of Urology at the Wuhan University in China titled "The Effect of Diethylstilbestrol on Inducing Abdominal Cryptorchidism and Relevant Genetic Expression in Rats" found that high doses of diethylstilbestrol played a significant role in the development of abdominal cryptorchidism in rats, although low dosages did not play a significant role. A similar study published in the August 2009 issue of the journal Environmental Health came to a similar conclusion. "Prenatal exposure to diethylstilbestrol increases risk of male urogenital abnormalities and that the association is strongest for exposure that occurs early in gestation," the researchers wrote.