Two intrauterine contraceptive systems safe and effective in preventing pregnancies

In a finding that could expand the use of one of the most effective forms of birth control, two intrauterine contraceptive systems that had lower doses of the contraceptive hormone, levonorgestrel, were found to be safe and effective in preventing pregnancies, according to an international study that included researchers at the Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center (LA BioMed).

The study, published in the December issue of the journal, Obstetrics & Gynecology, noted that the currently available higher-dose intrauterine contraceptive system has increased in popularity since its introduction in the U.S. in 2001 because of its safety, effectiveness and convenience: It doesn't require a woman to take a pill or take any specific actions immediately prior to intercourse.

But a recent survey found 60% of physicians rarely prescribe IUDs for women who have not borne children. In many European countries, they're only prescribed for women who have completed their families. Another recent study in U.S. family planning clinics found placement of the higher-dose intrauterine contraceptive systems failed in 19% of women who had not borne children.

The lower-dose intrauterine contraceptive systems are smaller than the higher-dose systems and, the study found, they are easier to use in women who have not delivered a child or have delivered only by cesarean section. Researchers at 138 centers across 11 countries tested the devices in nearly 3,000 women and rated placement of the smaller devices as "easy" in 90% of the women.

"By demonstrating the safety and efficacy of low-dose intrauterine contraceptive devices, this study will help expand the contraceptive options available to women who have not had children before," said Anita Nelson, MD, an LA BioMed lead researcher and corresponding author of the study. "Additionally, a lower dose system may be preferable to women who are seeking to reduce their exposure to synthetic hormones."

The study tested two intrauterine contraceptive systems: one with 13.5 milligrams of levonorgestrel and another with 19.5 milligrams. It found both to be highly effective and well-tolerated over a three-year period. The currently available higher-dose intrauterine contraceptive system has 52 milligrams of levonorgestrel.