Intrauterine devices, commonly known as IUDs, are normally used for long-term birth control. But, in a pinch, they can serve as emergency contraception if inserted into the womb within five days of unprotected intercourse.
In fact, a new study suggests these small devices made of plastic and copper coil are more effective than Plan B (levonorgestrel), the medication most frequently used by Canadian women for emergency contraception.
The researchers reviewed data from 42 studies carried out in the United State, Europe and China between 1979 and 2011.
“We found IUDs are very, very effective for preventing pregnancy after intercourse,” said Kelly Cleland, a staff researcher at the Office of Population Research at Princeton University.
“The pregnancy rate was .09 per cent – so less than one out of every 1,000 women got pregnant.”
By contrast, the failure rate is between 2 and 3 per cent for Plan B, which must be taken within three to five days after sex.
“I think women want the most effective option and the safest option. And I think the IUD is that option,” said Ms. Cleland, the lead author of the study which was published in the journal Human Reproduction.
But she acknowledges there is “a huge barrier to increasing the uptake of IUDs” – they have to be placed in the womb by qualified health-care providers.
In Canada, gynecologists usually perform this job, although a limited number of primary-care physicians are trained to do so, noted Edith Guilbert, a senior adviser to the National Institute of Public Health of Quebec.
Given the challenge of quickly booking an appointment with a gynecologist, it’s often easier for women to pick up Plan B at a local pharmacy. “It really is too bad because the IUD is an excellent contraceptive – and it can be left in place to ensure ongoing contraception,” said Dr. Guilbert.
It works in several ways. The copper creates a toxic environment for the sperm. Even if the sperm survives, it appears to prevent the fertilized egg from attaching to the lining of the uterus. According to the latest statistics, only about 6 per cent of Canadian women use an IUD as their main method of birth control.