April 28, 2004 — Taking the popular antidepressant drug Prozac late in pregnancy may be toxic to the fetus, a government report shows.

Mothers who take Prozac during the third trimester of pregnancy risk premature delivery, the report says. They also put their infants at risk of “poor neonatal adaptation,” including:

• Jitteriness

• Quick, shallow breathing

• Low blood sugar

• Low body temperature

• Poor muscle tone

• Trouble breathing

• Weak or absent cry

• Diminished reaction to pain

• Not getting enough oxygen while feeding

• Increased admission to special-care nurseries

Prozac taken by breastfeeding mothers, the report says, may retard infants’ early growth.

These aren’t Prozac’s only effects on reproduction. The report also says that the antidepressant also has “reproductive toxicity.” Adults taking the drug may find sexual orgasm difficult or impossible. And some women taking the drug may have changes in the length of their menstrual cycle.

The report comes from the Center for the Evaluation of Risks to Human Reproduction (CERHR). CERHR is part of the federal National Toxicology Program at the National Institutes of Health. Its job is to convene expert panels to look at possible threats to human reproduction — including child development.

The chairman of the 12-member Prozac panel was pediatrician and pharmacologist Ronald N. Hines, PhD, co-chief of pediatric pharmacology, pharmacogenetics, and teratology at Medical College of Wisconsin, Milwaukee.

“Patients should be aware that these are the risks of taking Prozac,” Hines tells WebMD. “They really should talk with their doctors about them before going on the drug.”

Tarra Ryker, spokeswoman for Prozac maker Eli Lilly & Co., says that the risks of untreated depression far outweigh those of properly prescribed antidepressants. Lilly is a WebMD sponsor.

“We don’t believe there is sufficient evidence to conclude that Prozac is a developmental or a reproductive toxin,” Ryker tells WebMD.

Prozac Benefits — Even During Pregnancy — May Outweigh Risks

“There may be some side effects that cannot be avoided, but the benefits of this drug may be so great they outweigh the risks,” Hines says.

And the benefits may be huge, says psychiatrist Mark I. Levy, MD, assistant clinical professor at the University of California, San Francisco.

“The main benefit is it is preventing depression at a vulnerable time in a vulnerable person,” Levy tells WebMD. “Prozac can be helpful in warding off postnatal depression, which is bad for a woman and bad for her baby.”

Women suffering from depression should not stop taking Prozac or other antidepressants, says Lee S. Cohen, MD, director of the perinatal and reproductive psychiatry clinical research program at Massachusetts General Hospital and Harvard Medical School. Cohen serves as a consultant to Prozac maker Eli Lilly & Co. He testified at the CERHR panel’s public hearing.

“If women stop antidepressant treatment during pregnancy, their risk for recurrence of their underlying depression is very, very high,” Cohen tells WebMD. “And depression during pregnancy is associated with bad outcomes for newborns and very bad outcomes for women.”

Hines, Cohen, Levy, and Ryker agree that pregnant women — or women planning to become pregnant — should not stop taking Prozac or other antidepressants until they’ve talked it over with their doctors.

“Women should not be overly alarmed about this report,” Cohen says. “It describes a series of symptoms that are very difficult to ascribe either to Prozac or to any other commonly used antidepressant taken before, during, or after pregnancy.”

Hines disagrees. While he notes that there is no “hard and fast” proof that Prozac is the definite cause of the toxicities the panel describes, the panel members find the evidence disturbing enough to recommend caution.

“We think that there is some concern,” Hines says. “We don’t think these toxicities are life threatening, but we feel that to be one hundred percent confident in the safety of this drug, it would be good to have more studies done.”

The panel concluded its report by recommending that more human and animal studies look closely at the effects of Prozac and other antidepressants on reproduction and child development.

At least one new study will soon arrive. At next week’s meeting of the American Psychiatric Association, Cohen will report findings from a study of 200 women with clinical depression who stayed on or stopped taking their antidepressants during pregnancy.

“We found that the risk for relapse of depression is indeed very high during pregnancy,” Cohen says. “I worry about pregnant women who have a history of depression and who stumble across this CERHR report. I worry that this huge effort on the part of CERHR will actually not help with the clinical care of patients.”