Вариант ургентной контрацепции

[dr_medvedev]

Vaginal Administration of Emergency Contraception May Be Effective

Laurie Barclay, MD;


July 22, 2005 — Vaginal administration of emergency contraception (EC) may be effective, according to the results of a small, open-label, crossover study reported in the July issue of Fertility and Sterility.

"Vaginal, as opposed to oral, hormonal administration avoids exposure to the gastrointestinal tract as well as first-pass metabolism in the liver, while allowing a direct local effect of sex hormones on the endometrium," write Eliran Mor, MD, from the University of Southern California Keck School of Medicine in Los Angeles, and colleagues. "The mechanism of action of orally administered EC is thought to be via a delay in ovulation with a possible direct action on the endometrium. However, data regarding the effect of vaginally administered EC on pituitary gonadotropin secretion are lacking."

In this prospective study at a university research center, five of nine regularly menstruating volunteer subjects received 1,000 µg of levonorgestrel with 200 µg of ethinyl E2 (twice the standard Yuzpe regimen dose) vaginally and the standard Yuzpe regimen dose orally one week later. The other four subjects received 1,500 µg of levonorgestrel (twice the standard Plan B regimen dose) vaginally and received the standard Plan B dose orally one week later.

Primary endpoints were serum gonadotropin, hepatic globulin, and androgen levels at baseline, at the time of peak levonorgestrel, and 24 hours later. The four regimens suppressed gonadotropin, hepatic globulin, and androgen levels to a similar degree, with a return to baseline levels after 24 hours.

"We conclude that high doses of levonorgestrel found in EC regimens lead to a transient direct suppression of gonadotropin, hepatic globulin, and androgen levels," the authors write. "This effect is similar after vaginal and oral administration of EC. Therefore, the vaginal route of administration of EC regimens may be as efficacious as the oral route."

Study limitations include the small number of subjects and inadequate power to detect significant differences in levels of suppression of gonadotropins, hepatic globulins, and androgens achieved with oral and vaginal EC.

"Our preliminary observations suggest that the vaginal route of administration of EC regimens, at double the standard dose, appears to be a viable alternative to the oral route and may prove to be equally efficacious in future clinical trials," the authors conclude.

Fertil Steril. 2005;84:40-45