Vaginal administration of emergency contraception might be an effective alternative to oral administration, according to results of a preliminary study published in the July issue of Fertility and Sterility, Reuters Health reports. Eliran Mor of the University of Southern California Keck School of Medicine and colleagues gave five women double the standard oral dose of the Yuzpe EC regimen -- levonorgestrel and ethinyl estradiol -- to administer vaginally and one week later gave the women the standard dose of the Yuzpe regimen to administer orally. Four other women were given double the standard oral dose of Plan B, which contains only levonorgestrel, to administer vaginally and one week later received the standard dose of Plan B to administer orally. Researchers found that vaginal administration of double the oral dose of EC caused the same temporary reduction in hormone levels that occurred when standard doses were given orally. Levels of gonadotropin, which when inhibited are thought to suppress ovulation, and other hormones decreased by about the same amount in the study participants with all four regimens and returned to normal levels within 24 hours, the study found. Lower doses of vaginally administered EC also might be effective at preventing pregnancy because the hormones are delivered directly to where they are needed, Mor said. According to Reuters Health, vaginal administration of EC also might lead to lower levels of nausea or vomiting than oral administration of the hormones. In addition, the lack of significant differences in gonadotropin suppression between the Yuzpe regimen and Plan B suggests that the ethinyl estradiol component of the Yuzpe regimen might be unnecessary, the researchers note. Larger studies are needed to determine whether the preliminary study findings translate to clinical efficacy, Mor said (Reuters Health, 7/21).