October 10, 2001
Exposure during pregnancy to the antidepressant drug venlafaxine does not increase the risk of birth defects
Researchers at The Hospital for Sick Children have concluded that exposure during pregnancy to venlafaxine, a relatively new and increasingly popular antidepressant drug, does not increase the chances of major birth defects.
The Motherisk study, published in the October issue of The American Journal of Psychiatry, demonstrates that the use of venlafaxine does not increase the rates of major malformations above the expected baseline rate of one to three per cent.
This is the first study to evaluate the safety of this drug during pregnancy. The study was able to ascertain the outcomes of 150 pregnancies after exposure to venlafaxine from women in seven different geographical centres. All of the women used the drug in the first trimester with 34 using it throughout their pregnancies.
Two additional comparison groups of women were used in the study, with one group taking medications including fluoxetine, sertraline, fluvoxamine and paroxetine. The other group of women were exposed to nonteratogenic drugs including, loperamide, echinacea, sumatriptin and dextromethorphan. Factors such as age, smoking status and alcohol intake were taken into consideration. Most women were followed up between six to 12 months after delivering their babies.
Of the 150 pregnancies followed, there were 125 live births, 18 spontaneous abortions and 7 therapeutic abortions. Among the group using venlafaxine, two major malformations occurred. In the two comparison groups, there were three major malformations (among the group taking fluoxetine, sertraline, fluvoxamine or paroxetine) and one major malformation (among the group exposed to nonteratogenic drugs). The results suggest there is not an increased risk for major malformations above the baseline rate of one to three per cent.
"A substantial number of women of child bearing age suffer from depression and coupled with the fact that at least 50 per cent of pregnancies are unplanned, it is likely women may use venlafaxine in early pregnancy. We have found that some women may choose to abort a wanted pregnancy due to the lack of information on the safety of a particular drug. In another one of our studies, due to the lack of information, a number of women elected to abruptly discontinue needed antidepressants after pregnancy was diagnosed," said Adrienne Einarson, the study's lead author and the assistant director of the Motherisk program at The Hospital for Sick Children.
"Women who have been diagnosed with depression prior to becoming pregnant and are being successfully treated, should not feel they have to automatically stop their medications as soon as a pregnancy is confirmed. Failure to treat depression during pregnancy can have serious ramifications for both the mother and child. This evidence-based information can be helpful to women and their health professionals when making a decision whether or not to treat depression with this particular drug during pregnancy," Einarson added.
Funding for this research was provided by The Hospital for Sick Children Foundation and an educational grant from Wyeth-Ayerst.
The Hospital for Sick Children is a health care, teaching and research centre dedicated exclusively to children; affiliated with the University of Toronto.
For more information, please visit www.sickkids.ca. Motherisk is a consultation service for pregnant or lactating women and their health care providers concerning the fetal risks associated with drug, chemical, infection, disease and radiation exposure during pregnancy. For more information, please visit www.motherisk.org.
For more information, please contact:
Public Affairs
The Hospital for Sick Children
555 University Avenue
Suite 1742, Public Affairs, First floor Atrium
Toronto,
ON
M5G 1X8
Canada
Phone: 416-813-5058
Fax: 416-813-5328