Prozac's effects on pregnancy and diabetes - fluoxetine

Science News, May 9, 1992 by Carol Ezzell

Women who become pregnant while taking the antidepressant drug fluoxetine, better known under the trade name Prozac, run no greater risk of having a baby with birth defects than women among the general population, a new study of the drug suggests. A second study indicates that fluoxetine can aid weight loss and improve diabetes symptoms among obese, Type II diabetics.

Roughly 5.5 million patients worldwide have taken fluoxetine since the FDA approved it in 1987, according to manufacturer Eli Lilly and Co. in Indianapolis. Many are women of childbearing age.

To determine whether fluoxetine taken by an expectant mother can damage her fetus, researchers led by physician David J. Goldstein of Eli Lilly followed the outcome of 271 fluoxetine-exposed pregnancies. Fifty-two of the women women became pregnant during a clinical trial of the drug, despite their use of birth control. The other 219 women joined a study on fetal fluoxetine exposure after becoming pregnant while taking the drug once it was on the market. Many of the women in both groups took fluoxetine throughout the first two months of pregnancy; a few continued to take the drug for the entire nine months.

Roughly one-fifth of the 271 women elected to have abortions, the researchers report. Of those who decided to continue their pregnancies, about 17 percent miscarried -- a miscarriage rate comparable to that of the general population, Goldstein says. Only seven women had babies with birth defects, such as a twisted gut, an enlarged mouth or fluid-filled scrotum. This 4 percent rate of birth defects is also comparable to that among the general population, Goldstein asserts. He and his colleagues presented their data in Baltimore last week at a joint meeting of the Association of American Physicians, the American Society for Clinical Investigation and the American Federation for Clinical Research.

"Overall, the data ... do not indicate that there's a significant difference from the general population risk" for miscarriage or birth defects among women who take fluoxetine during early pregnancy, Goldstein says. "But the precaution would be to avoid pregnancy if at all possible while you're being treated [with the drug]," until further studies confirm the finding, he cautions.

Lewis B. Holmes, a geneticist who studies birth defects at Massachusetts General Hospital in Boston, says the study is "nice to have" because no one had previously examined the effects of fetal exposure to fluoxetine. However, he says the study group is not large enough to rule out a pattern of rare birth defects. "Right now," says Holmes, "we're telling patients that there's no circumstantial evidence that there's a cause for concern [if they took fluoxetine during pregnancy] but that it hasn't been the subject of a systematic study." He adds that "there's no convincing evidence" that antidepressant drugs other than lithium cause birth defects in humans.

In another study reported at the meeting, Goldstein and a second group of Eli Lilly scientists examined fluoxetine's benefits in treating obese men and women with Type II (non-insulin-dependent) diabetes. All 278 volunteers followed a diet for diabetics; half received daily doses of fluoxetine, while the other half received placebo pills. After three months, the fluoxetine group had lost three time as much weight as the placebo patients. The fluoxetine group also had a blood sugar reduction nearly three times greater than that seen in the placebo patients.

"There seem to be beneficial effects [of fluoxetine] in patients with Type II diabetes," Goldstein concludes. George A. Bray, who studies diabetes and obesity at Louisiana State University in Baton Rouge, concurs. "The drug is really treating the obesity, not the diabetes," says Bray. "But if you treat the obesity in Type II diabetics, you are doing the most important thing you can do to correct their diabetics."