Aborted Fetus Study Links Fertility Drug To Possible Birth Defects
LOS ANGELES (AP) _ A study in which female sex organs were taken from aborted human fetuses and transplanted into mouse kidneys suggests women who use a common fertility drug may bear daughters with reproductive birth defects.
But the company that manufactures Clomid said the dosages of the drug used in the study apparently were far higher than those taken by infertile women.
Among daughters of women who took Clomid since it hit the market in 1967, ″as far as we know there is no increase in fetal malformations of any kind over those to be expected in the normal population,″ said Dr. Marjorie Newport, who monitors Clomid studies for Merrell Dow Pharmaceutical s.
Even the study’s chief author, biologist Gerald Cunha, said Tuesday it isn’t known if the defects found in the Clomid-treated transplanted vaginal, uterine and fallopian tube tissue would occur in daughters of women who took the drug.
That’s because researchers don’t know if the drug in a woman’s uterus and blood can cross the placenta into her developing infant, and if it does, how much of the drug reaches the fetus, said Cunha, a professor of anatomy and obstetrics-gynecology at the University of California, San Francisco.
″If the (developing fetal) female reproductive tract is exposed to significant levels of Clomid, it can have deleterious effects,″ Cunha said during a telephone interview.
Clomid, the brand name for clomiphene, spurs ovulation, or the release of eggs from the ovaries to the uterus, in women who are infertile because they can’t ovulate spontaneously.
The university said in a statement Clomid has been taken by millions of women, making it the most commonly used fertility drug in the United States. Newport said at the least, Clomid is among the most widely used.
Dosages used in the study appear to be ″significantly higher than those that would be used in humans, and the duration of use appeared to be much higher,″ but the matter ″will be thoroughly investigated until everyone is satisfied,″ Newport said from Cincinnati.
Cunha said dosages used in his experiment caused thickening of tissue lining the vagina and inhibited development of uterine muscle, uterine glands and fallopian tubes.
When girls born with such defects reach child-bearing age, the malformations can cause ″potentially fatal tubal pregnancies (where the fetus attaches to the wall of the fallopian tube rather than the wall of the uterus), premature delivery and an increased incidence of spontaneous abortion,″ the university statement said.
In the study, reproductive organs of aborted human female fetuses were transplanted under the membrane surrounding the kidneys of mice whose immune systems are crippled so they can’t reject the implants. The method allows the transplanted tissue to grow normally for up to eight weeks.
Cunha said the malformations were very similar to those produced by DES, or diethylstilbestrol, which was removed from the market in 1971 because it was linked with a high incidence of reproductive malformations and a rare form of vaginal cancer in the daughters of women who took DES to prevent miscarriages.
Newport said Cunha’s study ″sounds scary on the surface. But there’s so little correlation with the real-life situation it needs a lot more investigation before anyone gets overly concerned.″
″The company’s position at the moment is not one of undue concern,″ she added.
But Cunha said he also treated the transplanted sex organs with DES and found it caused defects similar to those caused by Clomid.
The study by Cunha and his colleagues in New Jersey and Japan was published in November’s issue of the journal Human Pathology, but was announced Tuesday by the university.