Lawsuits are being filed in Canada and the U.S. against the maker of an increasingly popular contraceptive, alleging that women haven’t been properly warned about rare but potentially serious risks associated with the intrauterine device.

In 2013, 52 uterine perforations involving the Mirena IUD were reported to Health Canada -- a rate of one perforation per week. And some women say the device migrated to other parts of their bodies after insertion.

The Mirena IUD, manufactured by Bayer, is inserted into a woman’s uterus to prevent pregnancy for up to five years. It was approved in Canada in 2002 and the province of Quebec now covers the $450 cost of the IUD insertion.

However, dozens of women in Canada are now filing lawsuits against Bayer over Mirena.

Jemila Shen, a Brampton, Ont., mother of two, told CTV News that she started experiencing severe abdominal cramping a year after deciding to use Mirena for birth control.

“It was very painful. I couldn’t walk,” she said. “I didn't want to get out of bed.”

When Shen went to have the device removed, doctors couldn’t locate it with an ultrasound. During surgery, the IUD was found near her hip bone.

Shen said she wasn’t warned that could happen.

“It sounds easy -- you put it in for five years and forget about it, but look what happened to me,” she said.

Bryan McPhadden, a Toronto-based lawyer who is in the process of starting a national class-action lawsuit against Bayer Inc., alleges the Mirena IUD has been found next to the lung, on the hipbone and on the tailbone of some patients.

He said that while Mirena works well for many women, labels on the package need to clearly warn users about the rare, but potentially serious risks associated with the device.

He said the current labelling of Mirena in Canada “doesn’t mention the possibility it might migrate out of the uterus and be found virtually anywhere in the abdomen.”

In July 2008 the U.S. Food and Drug Administration updated the labelling on Mirena to include this warning: “Delayed detection of perforation may result in migration outside the uterine cavity, adhesions...”

In Canada, there is no mention of migration, McPhadden said.

“The U.S. label is vastly superior to the Canadian label. It uses the word migration from perforation… In the Canadian label it only says perforation,” he said.

In a statement, Bayer said it’s aware of the Mirena-related lawsuits that have been filed in Canada.

“No class has been certified nor has any decision been made on the merits of these cases,” the company said.

“At Bayer, patient safety is our first priority. Mirena is a highly effective, reliable and safe option for the prevention of unplanned pregnancy and the treatment of heavy menstrual bleeding without a known reason.”

Bayer said that uterine perforation is a “rare complication associated with all intrauterine contraceptive devices/systems, including Mirena.”

It said that perforations occur at a rate of “between 1/1,000 and 1/10,000 insertions.”

Bayer said it helps educate Canadian healthcare professionals on the proper use of Mirena and encourages patients to get their first check-up four to 12 weeks after insertion. Yearly check-ups after that are also recommended, the company said.

Bayer said that information is included in the Mirena monograph and the patient package insert that comes with the device.

IUD complications rare with proper use: doctor

Many doctors say IUD complications are rare if the device is inserted properly.

“The risk of it migrating out of the uterus is zero if it is in the correct position to start with,” said Dr. Amanda Black, an obstetrician-gynecologist at the Ottawa Hospital and chair of the Society of Obstetricians and Gynecologists of Canada’s Contraception Awareness Program.

Black said the device is growing in popularity because it is an effective form of contraception.

“We see it is being used by more and more women each year,” she said.

The onus is on doctors, or those inserting the device, to make sure the IUD is in the right position, Black said, adding that proper follow-up is required.

But McPhadden said a number of his clients never received that follow-up.

Meanwhile, Canadian gynecologists are expected to release guidelines next year on all contraceptives, including Mirena. The guidelines will address how the risks of uterine perforations and other complications can be minimized.

With a report from CTV’s medical specialist Avis Favaro and producer Elizabeth St. Philip

FULL STATEMENT FROM BAYER:

“Bayer is aware of the lawsuits that have been filed in Canada involving Mirena. No class has been certified nor has any decision been made on the merits of these cases.

At Bayer, patient safety is our first priority. Mirena is a highly effective, reliable and safe option for the prevention of unplanned pregnancy and the treatment of heavy menstrual bleeding without a known reason. Mirena has been available to Canadian women for more than 13 years.

Uterine perforation is a rare complication associated with all intrauterine contraceptive devices/systems, including Mirena. Perforation occurs at a rate of between 1/1,000 and 1/10,000 insertions. Most perforations occur at the time of insertion but some may not be diagnosed immediately. Bayer facilitates education and training for Canadian healthcare professionals on the proper use of Mirena. Regular follow-up with a healthcare professional is recommended to ensure the device is positioned correctly. The first post-insertion check-up should take place 4-12 weeks after insertion, and yearly check-ups after that are also recommended. Women using Mirena are also counseled to check that it is in place by feeling for the threads attached to the device, monthly. This information is contained in the current Mirena product monograph as well as in a Patient Package Insert that is written in simplified language and is included with each Mirena package. Additionally, the Mirena product monograph is available on both the Bayer Inc. and Health Canada websites.

We take the safety of our products very seriously and we continuously monitor the safety profiles of our products worldwide. We investigate reports on adverse events thoroughly and collaborate closely with Health Canada concerning the use, benefits and risks of all our products, including Mirena.”