IUDs are most effective emergency contraceptive

May 8, 2012, 4:19 p.m.

IUDs (one of which is pictured above) are the most effective form of emergency contraception, according to an analysis of all available data from the past 35 years. (Credit: Mara/Flickr Creative Commons)

Step aside, morning-after pill: Researchers have found that intrauterine devices (IUDs) are the most effective form of emergency contraception.

The study appeared in Human Reproduction on Wednesday and was the first to review all the available data from the past 35 years. It found that IUDs had a failure rate of less than one per 1,000 and were more effective than the so-called morning-after pill.

If left in place, an IUD – a small plastic and copper device that's inserted into the womb by a trained medical professional – can also protect women from unwanted pregnancies for up to 10 years, depending on the brand.

Researchers looked at data from 42 studies carried out in six countries between 1979 and 2011, which included information for eight different types of IUDs and 7,034 women.

When used as emergency contraception, IUDs ought to be inserted within the five days following unprotected intercourse; that rule was followed in about 74 percent of the studies that were analyzed.

Out of 7,034 post-sex IUD insertions, there were 10 pregnancies.

First author Kelly Cleland estimated at least 36 percent of pregnancies worldwide to be unintentional. "We already know from previous research that IUDs are very cost-effective forms of regular contraception," she said in a statement. "This study is the most comprehensive review to date of the efficacy of IUDs used for emergency contraception, and our results provide clear evidence that they are a highly effective method of emergency contraception, as nearly 100 percent of users overall did not become pregnant after unprotected sex when an IUD was inserted post-coitally."

The next-most effective emergency contraception method is the morning-after pill – ulipristal acetate, in science speak – which has a failure rate of about one to two percent.

That's at least 10-20 times higher than IUDs, said Cleland, so she and her team concluded "that IUDs should be included routinely as an emergency contraceptive option whenever feasible and appropriate."

But researchers found that 85 percent of U.S. clinicians never recommend IUDs for emergency contraception and 93 percent require at least two visits for an IUD insertion – one to acquire the IUD and one to insert it.

"This is an extremely difficult problem to deal with," said researcher James Trussell, "especially as in many countries women can just go to their local pharmacy to obtain the 'morning after pill', but virtually no women know to ask for an IUD and many family planning clinics and surgeries do not offer same-day insertion. Offering same-day insertion would remove a huge barrier to the greater use of IUDs."

The cost is also a major factor in the use of IUDs on the southside, where nearly 74 births out of 1,000 were to a teenage girl in 2009. IUDs are often covered by insurance, but affordable health care is certainly not a given in the lives of people who live in South Los Angeles, and without it, IUDs run between $500 and $1,000.

Despite that up-front cost, IUDs end up being more cost-effective over time than other methods of birth control, since they last for years.

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Photo by Mara via Flickr Creative Commons.

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