British Columbia is the latest Canadian province to join a lawsuit against the makers of a popular birth control pill.

The Merchant Law Group is launching the a class action litigation on behalf of women who say they've suffered medical problems while using Yaz or Yasmin, what's referred to as a "fourth generation" progestin hormonal pill.

Merchant says it has received more than 200 complaints from women across Canada who "have suffered blood clots, pulmonary embolisms, gall bladder removals, and other serious medical emergencies," which the suit allege were caused by the pill.

The firm first launched an action with Ontario and Saskatchewan courts in December last year and expects more provinces to join in upcoming months.

Yasmin and Yaz were approved by Health Canada in 2004 and 2008 respectively. The pills quickly became bestsellers among teens and young women. The brands have been heavily promoted as a contraceptive that can also help control acne as well as the symptoms of PMS, or premenstrual syndrome.

The litigation aims to secure "significant" financial compensation for victims by the drug maker, Bayer.

The lawsuit claims that while all birth control pills carry risks, Yaz and Yasmin carry higher risks compared to other brands, because they contain a newer formulation that uses the hormone drospirenone.

Bayer says drospirenone helps prevent acne and counteracts estrogen-induced water retention, leading to less bloating and breast tenderness.

But the hormone can also increase potassium in the blood. If potassium levels become dangerously high, some studies suggest it can lead to heart rhythm problems.

Evatt Merchant, one of the main litigators on the suit, says the consequences to health from using these pills can be serious and long-term.

"It's not something that someone simply gets a blood clot and they go to a hospital for a weekend and they go back to their day to day lives," he told ctvb.ca from his office in Saskatoon.

"Some of our clients have been told to expect to be on blood thinners for years. These are serious medications you don't have to be on if you don't have to be."

The lawsuit's statement of claim alleges that Bayer failed to adequately warn patients and doctors about the increased risk of serious adverse injuries associated with use of Yasmin and Yaz as compared to safer oral contraceptives.

"Part of the suit will address whether it is safe, or whether it poses a higher risk than other forms of birth control," Merchant said.

More than 2 million prescriptions were filled in Canada for the contraceptive last year, according to IMS Health Canada.

The allegations have not been tested in court.