Copper IUDs are copper intrauterine devices. ABC News reported copper IUDs have been shown to be the best and most reliable emergency contraceptive for women, according to a study published in the journal Human Reproduction.
The study calculated that copper IUDs are almost 100 percent effective at preventing pregnancies, compared to the morning-after pill which has failure rates of up to 3 percent, wrote the Daily Mail.
Academics also said the IUDs can prevent pregnancy for up to five days after sex. The morning-after pill on the other hand needs to be taken within 72 hours (three days) after unprotected sex to prevent pregnancy.
According to the National Institutes of Health (NIH), copper IUDs are a form of birth control placed in a women’s uterus to prevent pregnancy. A T-shaped device, it works by releasing copper to physically prevent sperm from fertilizing the egg.
They can also prevent any fertilized eggs from implanting in the uterus. They are about the size of a match and can stay in the uterus for up to five years.
The study analyzed data from 42 studies conducted in six different countries (China, Egypt, Italy, The Netherlands, the United States and the United Kingdom) between 1979 and 2011, said ABC News.
The data showed women became pregnant at a rate of 0.09 percent if they used an IUD, as opposed to 1-2 percent pregnancy rate on the morning-after pill. In other words, 99.91 percent of women who used an IUD as emergency contraception did not become pregnant, said NIH.
NIH added that nearly all the IUDs were devices containing small amounts of copper, and only a small number of plastic-only IUDs were included, in the older pre-1985 studies.
Furthermore the maximum length of time from intercourse to IUD insertion ranged from 2 to 10 or more days. Most of the insertions occurred within five days of intercourse, wrote NIH.
The study raised an important issue. According to study authors, about 85 percent of American clinicians have never recommended an IUD for emergency contraception, and 93 percent require two doctor visits for the IUD insertion, said ABC News.