Reluctant to have surgery, instead her gynaecologist fitted her with a device he said would prevent her from ever becoming pregnant again.

Essure is a permanent birth control device that consists of soft coils which are inserted trans-vaginally into the fallopian tubes to promote the growth of scar tissue and block sperm from reaching the eggs.

But Ms Bernius did become pregnant – three times – resulting in two terminations and a baby.

A year after Ms Bernius had her Essure fitted, she discovered she was four months pregnant, and immediately opted to terminate in a decision that left her traumatised.

"I was in shock. I thought there was something wrong with this baby, because this is not right," Ms Bernius said.

"I had to give birth to the baby in the toilet, which was horrific, and then I broke up with my partner."

After the termination, Ms Bernius' gynaecologist ran tests on the Essure, which indicated that it was properly fitted and operating as it was designed.

But three years later, with a new husband, she became pregnant again.

This time she proceeded with the pregnancy, but it was complicated by gestational diabetes and she was haunted by her earlier abortion and terrified the coils would poke the fetus.

When she gave birth to a little girl, she could not look at her without thinking of the first baby.

And then she became pregnant again.

Essure has become the subject of a major medico-legal battle in the United States, where celebrity lawyer Erin Brockovich has taken up the cause on behalf of aggrieved women who want to bring a class action against Bayer, the manufacturer, but are prevented from doing so by federal laws.

A Facebook support group for women with Essure problems has more than 18,000 members.

In June, the US Food and Drug Administration added information to its website about the risks of the procedure and announced that its obstetrics and gynaecological division would hold a public meeting on the risks and benefits of the device.

Now a group of Australian women want to have Essure deregistered by the Therapeutic Goods Administration.

The device was pioneered in Adelaide by the late gynaecologist John Kerin, who envisaged it as a game changer to reduce population growth in the Tthird World because it did not require surgery or anaesthetic.

But women have complained of side effects, from abdominal pain to perforated uteruses and unintended pregnancies.

Georgina Fry, who participated in one of Professor Kerin's early trials in 2001, said she subsequently experienced extreme pain during menstruation and has developed an allergy to metal and certain deodorants.

"I'm at risk of anaemia because I lose massive blood clots, similar to afterbirth," Ms Fry said.

"I'm in excruciating pain. I've had two children and it's like the early stages of labour."

Her gynaecologist has prescribed acidic tablets, though she is not convinced Ms Fry's symptoms are related to the Essure.

"She refuses to use it in her clinic because the long-term effects are not known, but at the same time they're very reluctant to say this is caused by that," Ms Fry said.

Bayer said Essure was more than 99.8 per cent effective in women who had the coils correctly placed, based on 10 years of clinical data, and it worked closely with regulatory bodies to monitor the safety of its products.

"Bayer stands behind the benefit-risk profile of Essure and takes all adverse event reports seriously," a spokeswoman said. "It is important that women who have questions or who experience side-effects speak with their doctor."

Nicole Russell recently had her Essure reversed after suffering from pain, fatigue and extreme smell sensitivity – though she was initially told it could only be done by hysterectomy.

She believes the device gave her heavy metal poisoning. "I've had no life for the past four years," she said.

"There's a pile of evidence they need to be taken off the market. But the TGA are still allowing it."

But biotechnology law researcher Wendy Bonython said registration of a medical device by the TGA was not "an iron-clad guarantee" of its safety.

"The question is really whether there was sufficient information available at the time of registration to support that risk benefit analysis by regulators," Associate Professor Bonython said.

"It's axiomatic that the more times a device is used, the greater the likelihood that even rare complications will be observed. It is also true that in order to achieve a sufficient number of usages to identify those risks, the device must be registered for use."

Royal Australian and New Zealand College of Obstetricians and Gynaecologists vice-president Steve Robson, who worked under Professor Kerin during the product's development, said all contraceptive measures had side effects and failed in some women.

But he did not use Essure in his practice because it was so difficult to reverse.

"There's no technique that absolutely everybody is happy with," Dr Robson said.

"You've just got to make sure that people are well informed about what's good and what's potentially a negative and one of the issues with Essure is once they're in, they're incredibly difficult to get out."

The most recent analysis of studies that have been conducted on hysteroscopic sterilisation methods such as Essure found that the evidence on the effectiveness and risk factors of these procedures was poor quality.

More research needed to be conducted into complications and unintended pregnancies.

Ms Bernius, who was too depressed to continue with her third pregnancy, successfully sued her gynaecologist in the NSW District Court last year for negligence and breach of contract because he assured her the device was working after the first pregnancy and failed to advise her to use further contraception.

In November she finally got rid of the Essure, by hysterectomy, but the pain lingers.

"I feel so blessed that I've had three healthy kids, but I feel for the two souls," she said.