Article: Diethylstilbestrol

Diethylstilbestrol
Systematic (IUPAC) name
4-[4-(4-hydroxyphenyl)hex-3-en-3-yl]phenol
Identifiers
CAS number	56-53-1
ATC code	G03CB02 G03CC05, L02AA01
PubChem	3054
DrugBank	APRD00920
Chemical data
Formula	C18H20O2
Mol. weight	268.35 g/mol
Pharmacokinetic data
Bioavailability	?
Metabolism	?
Half life	?
Excretion	?
Therapeutic considerations
Pregnancy cat.	?
Legal status
Routes	?

Diethylstilbestrol (DES) is a drug, a synthetic estrogen that was developed to supplement a woman's natural estrogen production. First prescribed by physicians in 1938 for women who experienced miscarriages or premature deliveries, DES was originally considered effective and safe for both the pregnant woman and the developing baby. A double-blind study was not done until DES had been on the market for more than a decade (Dieckmann, 1953). Even though it found that pregnant women given DES had just as many miscarriages and premature deliveries as the control group, DES continued to be aggressively marketed and routinely prescribed.

In the United States, an estimated 5-10 million persons were exposed to DES during 1938-1971, including women who were prescribed DES while pregnant and the female and male children born of these pregnancies. In 1971, the Food and Drug Administration (FDA) issued a Drug Bulletin advising physicians to stop prescribing DES to pregnant women because it was linked to a rare vaginal cancer in female offspring. DES was, however, never banned and was continued to be prescribed in the U.S. and other countries well beyond the 1971 date (1978 in most European countries and even as late as 1994 in some third world countries).

More than 30 years of research have confirmed that DES is a teratogen, an agent that can cause malformations of an embryo or fetus. However, not all exposed persons will experience the following DES-related health problems.

• Women prescribed DES while pregnant are at a modestly increased risk for breast cancer. A new study shows DES daughters as having a 2.5 fold increase in breast cancer after age 40.

• Women exposed to DES before birth (in the womb), known as DES Daughters, are at an increased risk for clear cell adenocarcinoma (CCA) of the vagina and cervix, reproductive tract structural differences, pregnancy complications, infertility, and auto-immune disorders. Although DES Daughters appear to be at highest risk for clear cell cancer in their teens and early 20s, cases have been reported in DES Daughters in their 30s and 40s (Hatch, 1998).

• Men exposed to DES before birth (in the womb), known as DES Sons, are at an increased risk for non-cancerous epididymal cysts and auto-immune disorders.

Researchers are still following the health of persons exposed to DES to determine whether other health problems occur as they grow older.

Current research also looks at DES Third Generation. Third Generation refers to the offspring of DES Sons and Daughters. There is not yet much information available because the Third Generation are at an age where they can start to be physiologically affected by the DES exposure of his or her parent(s).

Third generation injuries are associated with preterm labor or deliveries resulting in premature birth and cerebral palsy, blindess or other neurological deficits or death of a child. One DES Daughter had a child who, at the age of four years, had such a severe case of cerebral palsy that the child was unable to turn himself over; the cerebral palsy was linked to the DES exposure of the mother.

Another study (J Pediatr Hematol Oncol 2003; 25:635-636.) found DES to be transgenerational, meaning that the maternal grandmother had taken DES while pregnant but the mother did not experience any health associated with the DES exposure. This was realized when a rare tumor was discovered on a 15 year old girl.

See also

• List of cancer clusters