A British Columbia court has agreed to allow a class-action lawsuit to proceed and to be headed by the case of an infant born with a hole in her heart after her mother took the antidepressant Paxil (paroxetine).

The mother, Faith Gibson, is suing GlaxoSmithKline Inc. (GSK), the maker of Paxil, alleging it caused her daughter’s birth defect and that the company knew or should have known of the risks.

The now seven-year-old girl is not expected to fully recover from her injuries.

An estimated 200 Canadian infants may eventually belong to the class because their mothers were prescribed Paxil during pregnancy. The drug allegedly causes damage to the brain, kidneys, heart and lungs of newborns and the product label warnings were inadequate, says the Canadian complaint.

Plaintiffs in the U.S. have been awarded more than $1 billion to resolve 800 cases so far, reports Bloomberg, with an average settlement of $1.25 million. Cases continue to be filed.

Doctors were notified by the company in letters sent out by GSK September 2005 that cardiovascular defects could result in the unborn child from Paxil use by the pregnant mother. Gibson’s daughter was born two weeks before the letters were sent out.

The next year GSK revised the label to more clearly outline the potential risks even though the company already had received reports of birth defects in smaller case studies, says one attorney for the plaintiff.

Paxil was made available in Canada in 1993. The label at the time had a generic warning that it should not be prescribed to pregnant women “unless the potential benefit to the patient outweighs the possible risk factors.”

An estimated six million prescriptions for Paxil were written for women between 1993 and 2009 reports the Huffington Post Canada. The trial is not expected to be heard there for several years.

Paxil is part of a class of drugs called selective serotonin reuptake inhibitors (SSRI) used to treat depression. Zoloft and Prozac are also SSRI antidepressants and are also linked to birth defects. The U.S. Food and Drug Administration upgraded Paxil from a Class C to a Class D drug indicating it poses a risk to a fetus.

A paper published last month in the journal Human Reproduction warned women should avoid all SSRI antidepressants during pregnancy.

Paxil and GSK is also the focus of a U.S. Justice Department probe into how the drug was marketed and whether information on suicidal behavior in adolescents was withheld from U.S. drug regulators. GSK was also accused of courting doctors with lavish trips and incentives to promote its drugs, including Paxil, which was finally banned for those under the age of 18 in 2008.