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Popular antidepressant drugs can put fetuses at risk, Ottawa researcher concludes

April 6, 2006

By Tom Spears
The Ottawa Citizen

Pregnant women who take antidepressants in the Prozac, Zoloft and Paxil family risk damage to their fetuses, and potentially even the death of the fetus, an Ottawa researcher has found.

The study, published today in an obstetrics journal, shows antidepressants increase the risk of premature birth, low birth weight, seizures in the newborn baby, and fetal death.

But researcher Dr. Mark Walker, an Ottawa high-risk obstetrician, says he can't simply tell pregnant women to avoid these drugs, as untreated depression is dangerous too.

The new findings -- in the largest study yet of popular antidepressant drugs and pregnancy -- show that doctors and some expectant mothers have to make a hard choice.

"We know that pregnancy is a time when mood disorders are more common," he said.

"So somebody with a history of depression is more likely to have a relapse during the pregnancy. If there's any time when you want to be vigilant, it's during pregnancy -- particularly the post-partum period."

Currently, the Prozac-Paxil-Zoloft group is the main treatment for depression during pregnancy. They're called SSRIs -- selective serotonin re-uptake inhibitors.

Dr. Walker works at the Ottawa Hospital and Ottawa Health Research Institute, while teaching at the University of Ottawa.

He turned to Saskatchewan for the survey of 4,800 women who were pregnant between 1990 and 2000. Of those, 972 took antidepressants, and 3,878 did not.

Saskatchewan has a pro-vincewide database of drug prescriptions, and he was able to compare the women's and babies' medical records with their drug use.

The study found:

- The women using antidepressants had a significantly higher number of premature babies -- 19 per cent, compared to 12 per cent of the women not using SSRI drugs. (Both are higher than the Canadian average of seven to eight per cent.) He counted babies born after 37 weeks or less.

- Women taking antidepressants had more fetuses die -- 1.1 per cent of them, compared to 0.4 per cent of the control group.

- They had nearly twice as many babies with low birth weight (9.0 per cent, compared to 5.3 per cent.)

- Their newborns were four times more likely to suffer seizures -- 0.4 per cent, versus 0.1 per cent.

While seizures in a newborn infant are usually more frightening than dangerous, Dr. Walker thinks they could be a sign of drug withdrawal in these cases.

But the obstetrician says a doctor can't just automatically advise pregnant women to quit their medication.

"There are two messages. One is that every single case must be reviewed with a physician. I mean, someone who's having a depressed episode clearly needs to stay on the medication," he said.

For a pregnant woman who has been in generally good emotional control, "this may be a good time to stop anyway."

The study is published in the American Journal of Obstetrics and Gynecology.

Note: Reprinted with permission from the Ottawa Citizen.