IUDs reduce pregnancy rates compared to hormonal contraceptives

Women who have had intrauterine devices (IUDs) fitted as contraceptives are less likely to become pregnant than those who have hormone injections, a new review by Cochrane Researchers has found. The review, which focused on women in developing countries, also found a possible link between contraceptive method and disease progression in HIV.

An IUD, sometimes known as a "coil" (although IUDs are no longer coil-shaped) is a plastic and copper device that sits in the womb preventing sperm from crossing it and making its lining less likely to accept a fertilised egg. There are also IUD's which contain hormones rather than copper, which were not evaluated in this study. In many countries IUDs are not widely used, perhaps because they can only be inserted by skilled professionals. Women often experience pain after insertion, but IUDs may be preferred long-term to other contraceptive methods because they last for five to ten years and have no hormonal effects. Hormonal contraceptives, by comparison, have been associated with side effects and require more frequent visits to the health care provider for injections or prescriptions.

The researchers reviewed data from two studies comparing IUDs and hormonal contraceptives, which together involved 967 women. The first included women attending family planning clinics in Brazil, Guatemala, Egypt and Vietnam and the second focused on HIV-positive women in Zambia. In each study, women were randomly assigned to have an IUD inserted or to receive hormonal contraceptives. Hormonal contraceptives were given only by injection in the first study, but women were allowed to switch between pills and injections in the second. Overall, fewer became pregnant in the groups receiving IUDs. Drop-out rates were higher for those using hormonal contraceptives in the first study and for those fitted with IUDs in the second study.

Lead researcher Justus Hofmeyr, of the Department of Obstetrics and Gynaecology at the University of the Witwatersrand and Eastern Cape Department of Health, South Africa, said the study highlights issues of choice in contraception. "This information will be useful for counselling women regarding their choice of contraception," he said. "The importance of choice is suggested by the fact that fewer women stopped taking hormonal contraceptives when they were allowed to switch between different types."

There was also some indication that progress of HIV was slower in women using IUDs, although the researchers say further analysis of this effect is required. "A large, high quality study is urgently needed to shed light on these findings," said Hofmeyr. "Meanwhile, HIV positive women should be given the option of using an IUD."

More information: Hofmeyr GJ, Singata M, Lawrie TA. Copper containing intra-uterine devices versus depot progestogens for contraception. Cochrane Database of Systematic Reviews 2010, Issue 6. Art. No.: CD007043. DOI: 10.1002/14651858.CD007043.pub2

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